I posted a thread awhile ago about finding these on eBay as well -
http://www.ft86club.com/forums/showt...ght=Ammunition
So far there doesn't seem to be much information about them (or even a brand associated with producing them) other than them coming from China.
If anyone feels like biting the bullet and getting a pair of these, I'd love for someone else to be the guinea pig and fill us in on what kind of quality these are - I've been wanting flat clear side markers since the day I picked up my FR-S!