What you want is something like GCC's "-Weffc++" on steroids. In fact, what you really want is a refactoring browser.
-Weffc++ on steroids is pretty much what I'm looking for, yeah.
Xrefactory, Slickedit, possibly Ref++ (whose websites seem to have disappeared), and Devexpress Refactor.
I tried Devexpress Refactor and Visual Assist X. On C++, neither of them is up to the standard of ReSharper (although ReSharper gets to play with .NET languages, which is probably easier).
The problem is not so much that I'm refactoring C++. The problem is that I'm refactoring legacy C code, and trying to turn it into C++.
I'll look at the others, thanks.