Here's an article that shows one way that could be used to get a Chrome game onto an XBox 360.
http://grammerjack.spaces.live.com/b...8A7C!158.entry

It basically involves make your game an assembly, then writing a C# dummy project in GSE that just calls your Chrome Game.main function and it should just work assuming everything else is setup correctly.

Also if you want to know what people who know what they are doing can do with XNA in 4 days, check out Ben's entry into the GDC XNA Challenge. He tried to write a 3rd person RPG in 4 days. You can check out what he managed to do by visiting http://abi.exdream.com