http://www.tomshardware.com/2006/07/21/the_graphics_state_of_the_union/page4.html
Rumors have it that the R600, the next ATI graphics core, will consume even more power. We are certain that Nvidia's will as well, since the company must add an additional set of shader processors and organizational units for Direct3D 10. It is no wonder we have heard rumors of external graphics solutions with their own power supplies. The devices would plug into a PCI Express slot that links a card (or up to 32 of them) into the interface.
The only application where we believe this could be reasonable would be a user plugging it into a notebook and a desktop. Then you could turn a weak notebook into a gaming system and have a similar experience on both systems. That would be awesome, but if this only solves a power issue it is an asinine answer to something the CPU world has already dealt with.
Just what my laptop needs!
"Why don't you zip it, Zipfero?" - fraich3