While I doubt the rims are actually a 26" and not a 700c, here's this link (although it's set up for a multispeed cassette, so you may one laced to a new rear hub; really just mroe money though):
http://www.nycbikes.com/item.php?item_id=669
And heads up, I have heard these guys can be a nightmare to deal with if something goes wrong.