Ahh, you consider buying a Blade 2000, but don't have it yet? Then be sure that it has a UPA based (inofficially) Xorg-supported frame buffer in it. Take one with ffb or afb (Creator 3d or Elite 3d). The Expert 3d on the other hand (btw a PCI 2.2 card with 3DLabs Wildcat chipset [without open-src drivers]), won't work at this time (although an unaccelerated dumb frame buffer driver derived from wsfb might work in the future).
See the SPARC-Xorg HCL for more info: http://www.opensolaris.org/os/project/fox/SPARC-Xorg/
