Microsoft tried to by Sega before CSK sold them to Sammy and they refused. Sega offered to sell themselves to Nintendo before they went third party but Yamauchi nixed the idea because he didn't want Nintendo to assume Sega's massive debt. I am sure MS would still be interested in picking up Sega, the hurdle would be whether Sega/Sammy would be open to the sale.
As I've said in "Sega Sammy dumping 400 employees" thread, I don't care who picks up Sega as long as they right the ship. Whether it be Sony, MS, or Nintendo doesn't matter, what matters is getting Sega back to the most versatile AAA software developer in the industry. Sega used to be able to make a AAA title in any genre. Now they are C- all the time with AM2 being long AAA development house.
