I want to make a 36" railing around my 8'L X 5'W utility trailer that will have five pipe sockets with an ID that will accept 1/2" PVC pipe. Then I will make five ribs that will bow into the sockets to form a covered wagon shape. I want to have this fitted with a waterproof canvas that can be secured under the trailer' I would like a window in one end and a zipper door in the other. What do you think?

That should work. We had a similar set up, but the arches were made of heavy duty aluminum piping convered with a thick mil poly. The poly had sleeves with a wire cable running through each rib and were tighten in place with wire cable nuts. For the floor we used wooden pallets covered with plywood. Each end we framed in with plywood and made a door. Also cut out an opening for an window a/c unit.

It was pretty big, about 8 x 16. We built benches that had hinged lids to store gear. On top we put thick cell foam, and slept on the benches. Normally we used the tent for guests that couldn't fit into trailer or cabin. If I can find an old picture I'll post it.