Gerald, a lot of us build our own. If you are into that, I'd recommend going to Northern Hardware. They have a sale about every month and have real good deals on open bed landscaping trailers. Advantages: The dimensions are just enough to hold your gear, reducing air drag. If done right, lighter. Disadvantages: Time.

Gerald,
Check on Ebay for Item number: 3695562171. Auction just ended for this trailer and nobody bid on it. Try contacting the seller by email and see if he is still willing to make a deal. You can see the photos online. The dimensions are larger than you indicated but you dont have to build it yourself.
Patrick

Hey that is really nice of you guys to respond.
Well me dear wife and I discussed the issue again and decided that a 5 x 8 enclosed is the right thing. Therefore the one in Florida which is 13' long is way to big. I did see that one though and agree it could work for someone lokking for a trailer that big.
I think I am going to check out the Northern Hardware guy. And as far as time goes: Yes I agree that is an issue, but you all know what the deal is: you will invest time and money if it is worth to you - and surfing even with a family still is very much worth to me/us.
Please let me know if you have any other ideas.
Gerald

If you can spare the change, try to dig up some aluminum square tubing for the frame. It can be bolted to the trailer and is much stiffer than wood construction. Steel is cheaper but face it, we all spend $ to get a board that is a pound or two cheaper. I used thin (dagnabit, I forget the kind of wood, but it's the tropical wood used as subflooring) plywood for the skin. Holds up better under weather and much lighter than thicker plywood.

I've done it a couple of different ways over the years. First trailer used the skin for strength with a light wooden frame. It was much smaller and needed special bolting methods to keep flex down (when you load about 100 lbs of long boards on top, it becomes more of an issue). Latest iteration is an aluminum/wood frame with a thin skin. As board designs got wider and Jr. started having his own boards, I had to change trailers.

I just replaced my trailer a few months ago. Got a great deal on a flat bed 4x8 traler at Harbour Freight tools (http://www.harborfreight.com). The kit was just under $200 for the trailer kit, its easy to put together and very light weight. The store is not too far from 85 on Indian Trail. The trailer that I just replaced probably had close to 100K M on it, and other than rust form Canadian winters, it was in not too bad shape. The flat bed option has less room on the trailer than the encolsed type, but its much easer to tow.
BTW, the box that I have is all wood, held up great over he last 14 years, still using it on the new trailer bed.

oh, last thing. get 12" wheels if you can, not the little 8's. At 75 mph, you don't want to think about how fast those little wheels are spinning and hope the lube is holding up.