I found this video describing newest AMD APUs in Notebooks:
AMD Details Ryzen Mobile 4000: Performance, Architecture, Features, Ryzen 9 4900H - YouTube
It looks like the integrated GPU is Vega Based:
It does not look like there is a Mobile GPU w/o integrated Vega Graphics.
Here are the laptop processor options.
They all have integrated Vega Cores.
Ryzen 2700X Memory Controller is not fun to deal with but Ryzen 3000 based CPUs are pretty good.
However.
Vega GPU drivers on PC are still blackscreening and crashing, as are RX5700XT ~ 8 months since launch now.
Fixing corrupted Windows 10 Pro because of an AMD GPU Driver crash on PC is bad enough.
Having to disassemble a laptop to fix it is an entire new level of pain.
Adrenalin 2020 interface is a mess but these new laptops are unlikely to allow use of Adrenalin 2019 GUI/UI.
If there was a Ryzen Mobile CPU without Radeon Graphics on a Laptop with Thunderbolt 3 I would consider it.
I have lots of experience with Intel CPU + Thunderbolt, Thunderbolt 2 and Thunderbolt 3 on Intel motherboards and addon cards working with eGPU boxes now.
Any new AMD Laptop with Thunderbolt 3 will be something new amd might not actually work with eGPU boxes.
I downloaded Avermedia tool to check if my Ryzen 2700X PC should work with their capture card:
Their 4K60 cards report problems:
In one case it advises to use a motherboard with an Intel CPU:
In other cases they complain about the USB3.0 ports (This is a known issue - some Avermedia cards have problems with some types of USB3.0 ports).
So according to the above it is likely I would have problems getting the 4K60 versions of Avermedia Capture cards to work with a Ryzen 2700X based motherboard and chipset.
I think I will pass on this and just buy a laptop with an Intel CPU and Nvidia Discrete GPU with Thunderbolt 3 support.
Thanks.
It looks like I have the following "low cost" options in Gaming Laptop space then:
Either one of these: OMEN Gaming PCs - Laptop and desktop computers | HP® Official Site
Which have a single Thunderbolt 3 port and last years Intel CPU and Nvidia GPU options.
For example the Omen X 2S
They are very expensive though - and the second LCD Screen seems to be a toy.
or:
A bit more sensible - the Omen 17: 
Slightly better CPU and GPU options than the Omen 15. Still only 1 Thunderbolt 3 port.
The above are on "sale" at the moment. I think new models are due on 2 April 2020.
Not sure it it is worth waiting for new Intel mobile CPU, based on this article:
Intel's Core i9 10980HK promises 5.3GHz, good luck hitting it in your new gaming laptop | PC Gamer
Nvidia are suppost to be launching "Super" versions of their Mobile GPUs though.
Thanks.
Ryzen 4000 mobile series processors only have 16 PCIe 3.0 lanes available. 8 for graphics and two sets of PCIe3.0x4 for storage.
Perhaps asking for Thunderbolt 3 interface on these new AMD Ryzen 4000 mobile series APU is too much to ask in this case.
Ryzen 3000 desktop series have lots of available PCIe 4.0 bandwidth available which could be used to drive Thunderbolt 3.
A few AMD X570 Motherboards have Thunderbolt 3 built in or Thunderbolt 3 headers on the motherboard required for additional Thunderbolt 3 Card.
This seems to be the best place to get news on new Thunderbolt 3 enabled devices:
Thunderbolt Technology Community
Dell Screws Early Adopters With Its Failed Alienware Area-51m Gaming Laptop
Dell demonstrated an astonishing amount of chutzpah today when it unveiled a second-generation Alienware Area-51m — and declared that whoops, the first-generation of the “upgradeable” laptop isn’t actually going to be upgradeable after all. The company has officially stated that: “Area-51m R1 only supports GPU upgrades within its current generation of graphics cards.”
First, a refresher: The original Alienware Area-51m was a desktop replacement laptop with a socketed CPU that could be swapped for other chips and, at least in theory, the ability to upgrade to different graphics cards in the future. An Alienware spokesperson claimed last year that Dell was committed to providing upgrades for the platform, but apparently what Dell meant by that was that it would only provide upgrades within the product family. In other words, if you have a 1660 Ti, you could swap up to an RTX 2080. What you won’t be able to do is improve to any graphics card better than that.
This Has Always *Literally* Been the Problem
The reason laptop graphics cards aren’t upgradeable has nothing to do with AMD, Nvidia, or the PCIe standard. The reason laptop GPUs can’t be upgraded is that no OEM has ever felt it would be profitable to create and commit to supporting a platform for multiple product generations. Laptop GPUs have to be built to very strict size tolerances, which is why there’s never been a single common standard. What Dell promised to do last year, effectively, was to create one, specifically for its Alienware 51-m line of products. Building a common laptop GPU card standard would allow a Dell Mobile (or what have you) RTX 2080 to be swapped for a Dell Mobile RTX 3080 or 4080 when the time came because all of these cards would use the same, Dell-designed form factor.
Dell is going to design custom mobile GPUs to fit its various XPS and Alienware laptops no matter what. This isn’t about whether the company was willing to build a custom GPU. It’s a question of whether Dell was willing to commit to building a series of compatible custom GPUs over time, in order to provide the market with an actual upgrade path. The answer? Even after promising customers that it would provide an “upgradeable” GPU, no, it wasn’t.
I refuse to let Dell even a little off the hook for this. The company communicated that it would provide further upgrades, and it knew damn well that “upgrade” is generally read to mean “components introduced after the laptop’s purchase date,” not “alternate hardware I could have bought at the time, but didn’t.” This was a laptop specifically and directly sold on the promise of offering a compatible platform for future hardware.
“Gamers have made it clear that they’ve noticed a lack of CPU and GPU upgradability in gaming laptops. We decided the best way to deal with that problem was to launch an upgradeable laptop at a substantial price premium, then provide no actual upgrades for it.” — Image by Dell, alternative caption by ExtremeTech
Declaring that the use of a socketed Intel motherboard made the Area-51m “upgradeable” in some fashion now looks like the profoundly cynical move of a company that never intended to deliver what it promised. It was always obvious that Dell’s ability to deliver an upgradeable CPU would hinge on whether Intel launched 10th Gen chips on its existing motherboard platforms or if it required new motherboards. The question of GPU upgrades, on the other hand, was always going to hinge on what Dell was willing to make available. The Area-51m website still claims that the product offers “CPU and GPU upgradability.” It neglects to mention that you’re literally paying for a feature Dell hasn’t previously bothered to support for an entire generation of customers.
And no — the Alien Graphics Amplifier doesn’t cut it. First of all, the Alienware Area-51m isn’t advertised as offering an upgradeable GPU via the AGA; it’s advertised as offering an upgradeable GPU. Second, the AGA is a $220 upgrade. That’s not a terrible price, but we’re already talking about customers who paid a premium for a laptop advertised with CPU and GPU upgradability.
Now Dell is launching a second-generation Area-51m. I’d detail and discuss it here if I had the slightest intention of recommending you give money to a company that treats its customers this way.
I don’t honestly care whether there’s a better chance that the R2 will actually get hardware upgrades. Every single customer that bought an Alienware Area-51m likely bought it expecting to upgrade the GPU much more than the CPU. The entire justification for buying the Area-51m (as opposed to one of Alienware’s other laptops) was the upgradeability. It’s true that Dell never specifically promised that it would offer GPU upgrades for the Alienware Area-51m. All it did was advertise that the laptop’s GPU was “upgradeable” while hiding behind a definition of “upgradeable” that no enthusiast would ever use. This is a distinction without a meaningful difference as far as I’m concerned.
Last year, I was willing to extend the benefit of the doubt when the company began shipping the RTX 2060 and 2070 modules it promised. As I wrote: “The flip side to all of this is that it’s rather nuts to pay $1,140 for an RTX 2080 if you already own an RTX 2060 or 2070. Frankly, it’d be pretty nuts to pay that much money to upgrade from an RTX 1660 Ti to an RTX 2080. But the first run of GPU upgrades for this hardware family was always going to be the weakest upgrade tier. What matters far more is whether Dell continues to put effort into the program in the first place.”
As is probably clear by now, I specifically repudiate my own previously optimistic guidance. CPU upgrades are nearly irrelevant for gaming. GPU upgrades are what matters.
Last year was supposed to be the introduction of the DGFF — the Dell Graphics Form Factor. After today, the company might want to change the acronym. I humbly suggest Dell Gaming-Fully Upgradeable, shortened as “DG-FU,” might be a better name instead. At the very least, it seems to capture more of the company’s actual attitude towards the gaming public.
Dell Screws Early Adopters With Its Failed Alienware Area-51m Gaming Laptop - ExtremeTech
Looks like I might be making my own "ITX Laptop" as a new project.
I found this example from a few years ago: mini-itx.com - projects - itx laptop 
This ASRock AMD Motherboard looks interesting, even though it only has 1 Thunderbolt 3 connector:
ASRock > X570 Phantom Gaming-ITX/TB3
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This PC Case looks interesting for Mini-ITX: https://www.fractal-design.com/products/cases/node/node-202/black/
