You can get a decent cyclo in small quantities from Aeromarine. They sell it for things like outdoor traffic surfaces:
http://www.aeromarineproducts.com/rock-pebble-deck.htm
They call it 300/21, and it is similar to what I have been using. If it is ok outside on an AZ pool deck it will be fine in a taillight. Aeromarine has the proper colorant for this material as well
