Exact same problem here.
I was running gentoo-dev-sources 2.6.10-r6. Installed vmware, tried to run in full screen mode, but it gave me crap about the kernel using framebuffer. Reconfigured the kernel to disable frame buffer support (:(). Rebooted with a small non framebuffer screen

, started Xorg, and everything looked fine. Everything ran fine absolutely no problems until I started vmware. Hard lock, had to power off.
Went to gentoo-dev-sources 2.6.10-r7, and no problems except some crap about no DGA modes....
So it would appear that only r6 is affected as the same problems are not present in r7.