AMD's fab spin-off called The Foundry Company might be interested in getting Nvidia onto its customer list. The first focus, of course, is ATI graphics and if they remain with some unused capacity they might invite Nvidia to join in as a customer.
This won't happen overnight, but we are quite sure that The Foundry Company will ask for less money than well-established TSMC and this would potentially mean more money for the graphics card vendors such as Nvidia.
The potential obstacle would naturally be the industry espionage, as it's highly unlikely that someone from The Foundry Company would actually talk to its AMD fellows as to how they successful taped out Nvidia's first chip; and such information is usually worth gold in this market.
TSMC is not better here, as once ATI tapes out a chip, Nvidia knows about it almost instantly and vice versa. We believe that bulk at The Foundry Company is about two years away from now, and for Nvidia, probably even further.