Or you can get Tru Turn to custom make one for you. When Marc (RCadmin) did the review of the UCD he had them make a 2 1/2 inch spinner that would accommodate an APC 15x6. I think they do the same thing everyone is talking about. Take a standard 2 1/2 inch spinner and enlarge the prop slots.
http://www.tru-turn.com/
Eric