I think I saw those at JC Whitney. I'll check and edit this with the thread if I find it.
Found them....try this:
SPINNERS
If I remember correctly, these are actually two parts. The spinner is held on the center cap by a screw going through a hole in the center cap into the back of the spinner. Some folks will use the entire center cap/spinner in their wheel, others will just use the spinner and drill a hole in their stock center cap and screw the spinner on.
If you are going to use the spinner only, you can just buy the $9.99/pair replacement spinners instead of spending $39.99 for the set and then not using the center cap portion.
Hope that helps.