The trailer is just a Harbor Freight folding trailer. I kind of wish I had waited for the heavier duty solid trailer instead of folding but this works great.
The whole thing is insulated minus the basements and door. Speaking of which, I went cheap on the door
Its a RV cargo door turned 90*I have it wired up with a AM/FM/CD, CB, and connections for my handheld 2M HAM to an external di-pole.
Right now it is wired just for 4-wire flat connection but considering upgrading to a 7-wire to utilize some power from the truck. Keeping the 4-wire for the wifes car.
It took my almost exactly one month to build. Luckily for one week when I was on-call for work we didn't have very many calls so I was able to knock-out a lot of the work.
With the slats in place I was able to slide them in and screw them down internally before adding insulation. It probably helped that it was raining during this part. I would take a hose and wet down a towel in the location where my bends would be. One towel on each side of the plywood. I tried to bend the thin plywood without wetting it down and it just snapped 
When it soaked in a bit, I was then able to bend it and screw it down 4 times per slat. Worked perfect! After that, cut up some insulation. This part was fun also as I had beads of insulation everywhere. A quick sharpen of the wifes non-serated kitchen knife and it cuts through the foam insulation with ease and no bits of foam flying everywhere.