For those interested in eventually running center caps:
I've gotten in touch with Racing Sciences, who currently manufacture adapters to allow the fitments of o-ring retained RAYS center caps to BMW, Nissan, and Lexus-fitment TE37SLs. They are currently working on a design to accommodate the ~65mm centerbore found on our wheels, and are hoping to have them out by Christmas. I will let you all know as soon as I hear from them that they are ready for sale.
2005 Elise, LRG on Ruby, Sport & Touring, Car #60 in the US