On Italian ebay, there is a Regina oro 5-cog 13-17 freewheel for sale http://cgi.ebay.it/ws/eBayISAPI.dll?ViewItem&item=3666339719
Just what you need to test your knees.
It looks nice on a show racing bike, but I wouldn't want to ride using it on most bikes.
--Steven MaaslandMoorestown, NJ