I ordered one from Harbor Freight too (a little munchkin trailer). It was a black one that came with a metal floor instead of having to put plywood down; otherwise the dimentions are the same as the one the OP is considering. I made the wooden sides for it - cheap pine boards from Home Depot just stained and varnished (that took longer than putting the trailer together). All total with lumber, hardware, and spare tire I have about $450 in it. I also had to buy a drop-down hitch for it. I bought it for hauling camping gear and such to trailheads and campsites since storage space inside the Jeep is limited. I've been very pleased with it. I also bought it thinking if I wanted to drive the Jeep to MOAB (from WA state) it would be nice to have to carry camping gear/tools/etc.
When I get back from Iraq a buddy and I are going to do the Highway 101 loop around the Olympic (WA) penninsula in the Jeep towing the trailer with our gear.
This E-Trailer site http://www.etrailer.com/Tires-and-Wheels/Americana/AM3S030.html
has some larger rims and tires (13" vs the 12" that come with the trailer) in the 4 on 4 bolt pattern. It's about 4" taller overall than the 12" rim with the 4.80 tires. They also have replacement hubs you can get in a 5 on 4.5" pattern (same as our TJs). I'm going to look into possibly changing out to a 5 on 4.5" hub after I determine if a larger wheel/tire combo (like a 15x6" black spoke with something like a 205/75/15" tire) would rub the frame or not. And I'd have to raise the fenders too if I did. Even with little trailers I'm trying to put larger tires on them.
In case someone's wondering about the little D-rings on the back of the trailer; I have a Harbor Freight towbar for the Jeep, and have the mounting brackets on the Jeep's front bumper. I ordered another set of brackets (they were only a couple bucks each) and mounted them on the rear of the trailer, and then put a couple small D-rings on the brackets. It matches the rear bumper on the Jeep. I was bored - and it looks cool (to me anyways). I also had to get gussets welded on my Jeep's rear bumper for the safety chains (it hadn't been done yet when these pictures were taken; neither was the Jeep wired for trailer lights at that time).