68K CPU @ 4GHz (dreaming)
133 or DDR ram slots for up to 4 gigs of ram.
Memory controller to ad as much chipram as you want from the system ram. Or you can use the GFX cards ram as chipram.
PCI and Zorro II/III/IV slots...
PCIe slots and even a AGP for kicks...
Some circuits to "retarget" any hardware banging software, forcing it to use the installed GFX card.
USB, on board network, support for much larger kickstarts than 512 kb (perhaps a 2gig flash unit), SATA, fire wire, + anything else i can't think of....