I finally got around to reading this paper by Oleg Kiselyov, Ralf Laemmel, and Kean Schupke. Basically, they've explained how to add object orientation to Haskell without changing the language at all - it turns out all the necessary features are already present in the language, but nobody noticed this before. It's fascinating reading. By the end of the paper, they've put together an object system that's a slight improvement on Ocaml's object system (and therefore a significant improvement over Java/C#/C++). There's real code too, check it out. Of course, some of the stuff they do would go down a little bit nicer with some syntactic sugar, but it's surprisingly palatable in the raw.