alot of mention of tru-turn spinners,which are the most expensive aluminum spinners out there,I have several of them they wern't cheap.
there are several less expensive brands of metal spinners Dave brown http://www.dbproducts.com/ which are close to half the price as the TT and they will cut the prop slots to order.

there is also these I found and have 2 of them, there inexpensive, polished,and come with a adaptor nut in many sizes, there 2 1/4 alum. spinner is 9.50 not too bad of a price for a upgrade from plastic, they don't cut the slots custom one size fits all, but its easy to open the slots up slightly, as long as your carefull .