Duck 51,
The ones that I have seen,were a 2X4 frame covered with barn roofing tin and the sildes and track were the hardware for a big sliding barn door. I don't think that there is a "sliding trap roof kit". It is a matter of what you can make work. If you know a club that has their trap houses set up with a sliding
roof, go take a good look at one and you will be able to build one. It ain't brain surgery.
Good luck,
Patrick Swartz