Saw this article, The Myth of the Interchangeable Programmer. It runs along the lines of the famous Mythical Man Month book by Fred Books, this time applied to off shoring.
Bottom line is that you may find that one developer may be doing 60% of the work of the team, or three developers 80%, and the more people you add to the team, the more you slow down the people who are actually getting something done. The author thinks that from his own experience, a team of eight is the max. I agree. (obviously, for huge projects, you need several teams, but he elaborates on that too).
It is funny, because a client just told me our rate for a senior WPF engineer was way out of their range, and they were looking to outsource it off shore...good luck to them! This is difficult, leading edge technology, and the kind of area where one good senior architect can do something in a week that could take a team of less experienced people months to do.