Trailers Unlimited here in Edmonton, Alberta, makes cargo trailers under the Shuttle brand name, with moulded fiberglass bodies at quite reasonable weights. They'll do custom sizes to some extent.
Catrinkabuilt her trailer from one of these.
The Shuttle has a tapered (in both width and height) nose - I don't know if that fits the plan as well as a constant-height v-nose.
In general, I think the key is to ignore the obvious suggestion in the product line descriptions to pick the "best" cargo trailer, because that usually means the heaviest. Since you don't need high load capacity, the cheaper line from a given manufacturer is probably more suitable.