The only 'big' company i could see them going for would be Sega, you never know - but at the moment I think Microsoft is seeing it's best strategy to not have internal studios, where they 'gasp' have to sell their stuff on their console only(limiting profits). They see the market being very pro-multiplatform for a long time to come. Instead they wanna fund big name studios for exclusives and out-bid Sony/Nintendo for anything that looks good early in development. i actually think they're starting to believe exclusives don't matter, and that there will be enough multi-plat content for them to get customers and they can make sure they're the lowest priced console by nickle and dimeing their buyers for live and accessories - using these profits to sell at a loss.