I think it would be a wasted effort to try to come up with a new fully custom computer, but what I think could work is a fully open graphics card, or full open A/V card, which works on standard buses.
Sure, there are open drivers out there, but with the hardware DRM built into Windows Vista those drivers will soon be history. Once all hardware is thoroughly DRM'd you can pretty much forget about innovation in graphics hardware as industry, the true customer market for Vista, will favor the lowest common denominator.
As far as a games machine goes, what about the GP2X? It's new, and it's open to development. I wonder what the Amiga community would think of a GP2X derivative in an all-in-one case with keyboard and mouse that connected to a television.
