I find it very interesting and have a prototype working based on Steve's mvc sample and another small sample from this thread. Using json.net to deserialize within the post action as I couldn't figure how to downgrade his FromJsonAttribute from .net 4 to .net 3.5, which I'm running in this case.
Wanted to know if anyone had put the Knockoutjs JavaScript library into production with asp.net-mvc and found any major issues?