I've been playing with Git on a jungledisk drive recently (which uses Amazon S3 behind the scenes).

The S3 costs are looking pretty cheap so far. I've backed up all my work on to there, and uploaded 2 private Git repositories. With Git, I've been pushing and pulling my local repository to the JungleDisk drive 3-5 times daily over the last 5 days. This could be a runner for cheap private Git hosting.