>>Do you know if they had a fiberglass fuselage?

You are correct that Mike Del Ponte was a co-conspirator for the original. He also was involved in the production of the ‘fleet’. They are conventional balsa/ply, foam wing and fiberglass cowl.

>>Do you know if someone kits that white mustang at the top of the page

It is a Sky Harbor R/C kit. I think they are no longer in business. The current pilot of the aircraft in the picture is not pleased with the flight characteristics.