I have searched here, GooBingHooVista'd the world and read this related question for VS 2010: How to configure Visual Studio to use different source control providers and the others linked. This answer: https://stackoverflow.com/a/6789773/492 is the most interesting so far, although the functionality seems to be based on a bug in VS. I would work for me although I'd rather it get it working properly.
I'm asking basically the same question fro VS 2012 - has the provider model changed &/or is it possible to have the VS integration switch source-control (SEO: version control) providers per project, rather than just per-solution?
Reason for asking: I have a projects in Hg & in Git. Git seems to be winning favour these days but presently Kiln (Fogbugz's linked repo) is Hg-only and most of my repos are there. I find it handy to be able to commit from VS with a couple of keystrokes (I set ctrl-alt-shift-C to File => Commit) rather than context-switching my feeble mind away from VS to do my housekeeping.
I'd be more than happy if needed to add an extension to do this.