Git and Team Foundation Server
I've started working on a tool called git-tfs, similar in some ways to git-svn.
https://github.com/git-tfs/git-tfs
A new offering from Microsoft: Git-tf
Announcement: Announcing Git Integration with TFS
Download: here
Source (CodePlex): here
I'm sure it's possible, but it's going to be very rube goldberg-ian in its construction and will most likely lead to more pain than pleasure. I suggest picking a source control system and going with it.
If you need real offline support then git is awesome, but windows support is still a bit flakey.