I've been wondering when someone would come out with a cloud-based IDE, although this isn't quite the same. I've always thought, wouldn't it be cool if Google came out with an online IDE, hosted on a GAE instance, with code saved in Google Code, allows you to build your code on their servers, and deploy to a dev GAE instance with seamless push to a production instance. For kicks (and probably an extra fee) you could have Google engineers do a code-review.