In some places the procedure is to edit your post, then double post to bump. Once the thread has been bumped, you delete the empty post, so it doesn't clutter things.
I don't actually know if that would work here, but if you want to keep your thread tidy, it's worth a shot.
This is really only a problem on forums where people have huge sigs, animated avatars, or banner ads in their sigs. Nobody around here has any of those things. Nope.