For now, we're gonna stick with themed avatars stored on the server, with the possibility of expanding later on so that established members can link to external avatars (though my particular part of the jury is still out on this).
The avatar I have is, indeed, of me -- I wanted the idea that the moderators of the board stood out a little to be in place. You'll find, when they post, that Jim, Shannon, and Ashton have personal avatars as well.
I would welcome submissions of themed avatars, certainly. I'm trying to keep them in a relatively consistent format ("Livejournal Friendly" -- 100x100, with a nested white and black border around the content), but if you don't mind me tinkering with the ones you've put together to make them fit that, I'm happy to take submissions in whatever form.
That said, I'd also prefer that you contact me by private message (there's a little icon over on the left, I think) with any submissions/requests, rather than posting to the thread, but really, get 'em to me however, and I'll put them under consideration.