I’d forgotten about this, but wanted to mention it quickly. A version of Hero Engine has come out that makes development of an MMO for indies very accessible. Hero Cloud trades up front licensing for royalties. I’d started to look at it months ago, but other things took priority. I’m back to thinking that it might be the way to go for the spy genre MMO I’ve been thinking about.
I’ll be taking another look at this in the near future as things develop and I’d urge any other indie to do so as well. It’s not XNA, but it does mean I wouldn’t have to do a lot of writing of systems or an editor to create areas.