http://cgi.ebay.ca/ws/eBayISAPI.dll?...STRK:MESELX:IT
So far there is only 2 known to exist.
Info on the cart can be found here:
http://tinycartridge.com/post/244978979/smart-boy-...
http://www.gamesniped.com/2009/08/07/nes-nintendo-...
Good luck only 2 days left.