Couple of questions. Could the top fit on any trailer? Say any 4x6 utility trailer, can the fiberglass pieces be cut to fit other size trailers?
How much weight could the top hold? Could you put an RTT on top. Maybe use metal instead of wood ribs?
The parts of the modular versions can be cut trimmed to length to fit other size trailers. The TrailTop straight rails are molded 8' long and would be trimmed to fit the roughly 4x6 top edge of a military trailer.
Weight capacity isn't a problem, here's a roof-top tent mounted to the TrailTop modular cover on my Jeep-tub trailer, which is abou 5' wide and 7 1/2' long, so the cover is much larger than a military trailer.
And these next photos shows a roof-top tent on a military trailer, this trailer has the two-piece fiberglass cover but there's no reason the modular cover wouldn't be as strong when built, since it's smaller in both length and width than the cover on the yellow trailer above.
Depending on how you hinge it, and what gas struts you use and where/how you attach them, the cover can be opened with tent set up: