Woohoo! I got it from Sparco.com (btw, the ONLY site that I could find that had stock)
http://www.microsoft.com/hardware/mouse/wie_info.asp
I can't wait for it to get here tomorrow. With overnight shipping (and, yes, it will ship today), it came to $85.61, so, no, it's not cheap, but I know it will be worth EVERY penny.