I know this was a requested feature... oh, way back right after the uBB boards were shelved and the current forum system was put into place, and we were told that there was a reason we weren't getting them (what the precise reason was is escaping me at the moment, since... it was quite some time ago).
With that said, quite a bit has changed since then. Is there any possibility of Premium users getting the ability to put a (smallish) signature image into their posts? Something on the lines of 400 x 100 wouldn't pose undue strain on computers, could be combined with a "Disable Signature Images" option if people don't want to bother loading them on slower machines, and would let the Premium users demonstrate a little more of our inherent creativity. (In case it matters, the 400 x 100 size is derived from the size of the WoWSig's, albeit slightly wider since I like round numbers).