Yea, with the performance being put out by single gpus now, data lane bottlenecks being taking care of and the fact a lot of games still have issues with duel or more cards most companies are just going towards single or duel support.
I wanted to reuse my current Quadfire R9 290X.
Only synthetic benchmarks and only a few selected games support or gain something with Quadfire. I knew that before building my PC, but it was my dream to have at least once a Quadfire setup.
Oh I understand, I really wanted to a have build like that as well. I however went the "fun" way (saying fun with max sarcasm) of getting a 220 watt FX9370 which left me the options of three motherboards. I really wanted to the Crosshair V Formula-Z, that has many PCI-E ports but some of them would put the video cards into each other. Plus the FX9370, that mobo, 4 hard drives in RAID 0 plus a SSD for system and the two Asus R9 290X was often hitting my wattage at or a little over 1000 watts. With me being a hardcore corsair fan, the PSUs I needed of 1500 watts was more then I wanted to spend at the time.