Since you're wanting something for everybody to wear, I think they'd more appreciate a userbar. That way they could still use their signature and have a custom userbar fit nicely underneath it. If it matters, the width is 360 pixels (for matching signatures).
I'm not sure if you'll like it, but yeah, I made a userbar. I can change the colors, placement, anything about it. Let me know?
http://i44.tinypic.com/212zasl.jpg
Also, a random banner that you can use if you'd want.
http://i42.tinypic.com/jingcl.png
If you like it, let me know and we can work out a very very cheap price. I don't expect much for my works because I'm new here. You can probably get a deal off of me too, I'm not sure yet how much my graphics will go for.