The ZMan:Its certainly written using XNA and c# becuase thats the only kind of app that XBLIG will accept. It uses exactly the same tools that you have access to.
I have no idea on the size of the team, but I've not known many big teams at MS Research I'd bet les than 10 people... I'm sure they had additional part time folk for doing art and sound and testing... either way team size isn't something that is relevant. If EA wanted to put 10 games a week through XBLIG then they absolutly could..
If that's true, then I guess my comment was unfair, but I still don't consider a Microsoft title (or an EA title) to be a "community" or "indie" game.
They can do what they like of course, but it would sound a little odd if their sales pitch were "Come to the Indie games section and see all the new Indie titles developed by Microsoft and EA.".
EDIT: Out of curiosity (I'm not a premium member): Did Kodu go through peer review?