I have some AMPRAA trophy's here ( from Australia) that are made out of a thick piece of perspex- 20mm, with a circle as you describe with a very large chequered pylon as the focal point with a couple of pylon models racing around the pylon.......all nicely engraved/ sand blasted. Very impressive- why don't you get hold of John Hughan in Melbourne and see if you can use the design, or at least make contact to the original artist. Big T.