Hi Tom, we've been using a combination of responders and Draper decorators for this. It has been in production for almost a year and has worked out pretty well so far. Simon, one of our developers, wrote a couple of articles outlining our API setup:

Part 1: http://techblog.tribesports.com/blog/2011/09/24/versioning-t... Part 2: http://techblog.tribesports.com/blog/2011/09/24/separating-a...