That's not particularly hard, I just tested out a solution using icons in the signature. Hopefully you're able to see it. I suppose it would be for the best though if Eich could let us know if the forum can handle image files in signatures.
Also I'm not sure stealing icons from Humon's site is the right way to do it, but well ...
Image files and gifs are fine in sigs. Just... don't make them too big or, if they are big, scale them down a bit using a little BBCode, because it's not fun having entire pages taken up by oversized signatures. Good solution, by the way. I'm not sure if there's a way to add another slot of info in the avatar area but, for now at least, this is a pretty elegant solution.
I like the idea Greger. Even if we don't use flags, we can just write what languages we know in the sigs or something. The only real use I can think of would be for the language learning thread, though. That said, I'm monolingual, so I don't really know what uses there might be. Maybe a quick way to know what potential areas of the world people live in?