I gave up on the 9.12 drivers, I managed through some vnc trickery to a single display up in crossfireX mode, and 2 GPUs were "visible", but judging from the performance, it looked like it really was just a single GPU.
Jumping through the hoops, I reverted to 9.10 - which gives me good dual GPU performance, but alas no OpenCL or evergreen IL instrutions.
What is most frustrating (apart from the time wasted on this exercise) is the near total lack of proper feedback channels. I work as a SW developer, and understands that bugs and regressions happens, but if bugs are not reported back to the developers, it is also impossible for them to be fixed.