The rest of the Portal 2 soundtrack would probably have to be picked up by a RBN authoring group, but I would bet good money that Harmonix is probably already working on or planning to officially release "Want you Gone". They did make "Still Alive" after all.
I didn't want to make a new thread and this seems to fit here so:
Has anyone tried to contact PopCap about getting the song at the end of Plants vs Zombies? It would have great harmonies lol.
Tubbs has a new home
Contacting whoever has the rights shouldn't be too hard, as the OST was released on Bandcamp. You'd just have to hit that "For all inquiries" button, fill out the form, and ask about who you'd have to contact. Then it should be easy from there (to contact them, that is, not necessarily to get an agreement).
I went to Harmonix and ordered a pepperoni pizza. Instead, they gave me a cheese pizza and told me that I could buy one pepperoni slice every week.