Update (19th March): I've added some additional info I received at the end of the post.
Jun 2013 Update: I've made the switch to Android. More info can be found here!
Rob Hutchinson, a talented programmer I used to work with, from nullcity.com has just release a game called Breeze on the Xbox LIVE Indie Marketplace. It was built using Kitae, his 2D XNA Game Engine. I'm really impressed with how this game turned out, and I think it's going to do really well in the marketplace. I thought I'd plug it here, as I know many readers are XNA coders :-)