Do you know of any stand-out libraries in this regard worth binding?

When I looked in to this last year, the best I could find was the boost library. It depends very heavily on template meta-programming, though, so it wouldn't really be bindable with any of the generality that it has in its native C++.

I ask because I'm doing a lot of graph stuff in Haskell right now, and I might be willing to put in the effort to do the binding--especially while I still have c2hs syntax fresh in the brain: I just finished a complete re-write of the mathlink library (brings Haskell to Mathematica -- announcement to follow shortly).

--Tracy