According to Entertainment Weekly, Sheldon will be getting a new roommate when Leonard moves out! Don't adjust your computer monitor, Leonard is indeed moving out!!!
The new roommate will be a human -- don't say "d'uh" too fast as Sheldon could have a Shelbot move in! ;) -- and it will be someone we know. Sheldon will learn a lot from his new roommate and it will be a terrific experience. It's unknown yet if the roommate will be a temporary or permanent one.