I haven't heard anything requarding BTX in the last few months. Is it a dead form factor? I see there are some mobos on the market that use the form factor, but not that many.
Due to the onboard memory controller of AMDs cpus, they can't use the layout as the memory is too far away from the cpu socket, so it never really caught on AFAIK AMD is also developing a layout that Intel cant use, because of the placement of the northbridge, children, the lot of them