While drumming up support for the new 360 avatar marketplace, Microsoft showed off how your little guy could dress up as a character from Gears of War, or Monkey Island. Turns out those were just the tip of the iceberg.
https://kotaku.com/you-can-dress-your-avatar-in-all-this-stuff-5332717/
Now that the marketplace is live, we can see that there are clothing options available for a range of games, from Star Wars (the upcoming Republic Heroes) to BioShock to Splinter Cell.
You can see a few of these new items above and below, modelled by yours truly.