What are the chances that nVIDIA buying out AMD or other companies namely Apple doing something along those lines?
Think how much it would be to put AMD back into the fight again:
1. Divert whatever relationships you have with Intel, because it would sour the day you bid for AMD
2. Shell a lot of money to cash out the old investors
3. Get into a huge legal spat with Intel to get a new x86 license
4. Bring in new management, because you would want your new company in the hands of professionals, not on the hands of that bunch of amateurs that manage AMD today
5. Shell out another load of money to build engineering teams, testing facilities, etc
6. Quit or roll AMD debt
7. Wait some 4-5 years until the products developed by the new teams reach the market.
8. Pray for those products be competitive against Intel
All that to get IP from a company that has a presence in a mature market and facing a competitor a lot bigger than you.
If you are really serious about this kind of money and effort you wouldn't buy AMD, you would start an ARM company today. If you are really keen into x86 you wouldn't buy AMD either, but would develop your x86 design and manufacture it through IBM, much like Transmeta did.
AMD as a company isn't interesting at all to anyone, but some of their patents should attract a lot of bidders once they go to the market.