It's really easy to push to two remotes. I have a tfs service account setup and using git and also a github account. I like tfs's project and issue tracking better but want the public repo available on github.

git add remote <name> <url> git add remote <name> <url> then create a shell script that checks both remotes for the latest if one is greater than the other merge the two if they are the same then push to both. Then just always push with that script.

Just how I've handled it so far. That said a autoMagical way of handling it built into github/git itself would be cool.