And it doesn't quite qualify as a distribution platform so much as a way to share your source code and media with other developers.
yep,commerical xbox distribution at this time is a no-no, unless you share your code/media,to other developers only.
though develop it for the pc,and you can distribute it however you like,a msdn geezer told me that himself,well,on the forum,as that was one of my first questions when i tried it.