Archie, in Tom Stroh's book, page 22, it states that there are 15 roulette chips that have been identified as unavailable or non-existant. It stated that at that time there were none known at the hands of collectors!!!
I have been looking and watching for these 15 chips and in ebay there has been two sales of one of these fifteen, the brown satellite has been sold twice and the price, if I remember was closed to the $100 ea. I am not aware of any other of the 15 showing up until the ones I obtained today!!

Luis