This is another one of those that should have been a no-brainer, but I never thought to even look for it: a way to perform Mercurial operations from within Visual Studio.
It turns out there is a plug-in for this: HgSccPackage. You can find it on Microsoft’s Visual Studio Extension Library or at this website.
Hernan Garcia has more about it (including screen shots) here.
Clive's YABB: lessons learned and promptly forgotten from the wonderful world of programming 