That looks like the smaller Harbor Freight trailer with an extended tongue. I think I have the same trailer, but I thought it would be too short to carry two Rev 11's using J hook carriers. Can you provide any more photos or info? I would love to mod my trailer in a similar manner.
It is the smaller HF trailer, the 12" tire model. I welded the rack to the back and front of the trailer, so they are about 54" apart. On my Outback, the Jracks sit at the two widest points of the boat, before the hull narrows again.
The tongue is extended about 2 feet in this pic. It is a 10' piece of 2" steel tube. It can extend about 2 more feet (hopefully to accommodate an Adventure Island someday, with an additional set of cross bars on the tongue). This also allows for it to take up the least space in my garage, as I can slide the tongue back.
I've got about 600 miles and 15 trips on it so far, and its working PERFECT! Its narrower on the bottom so that it fits in my garage better, against a work bench so it takes up the least space. The top of the small kayaks barely touch the garage door when I wheel it in. I'll try to take some more pics tonight.
One thing to note: All of the steel is 1/8" and I did weld a 2" spine down the center of the trailer and reinforced the front and rear of the trailer frame by welding steel plates to box the steel. The HF trailer is pretty flimsy C channel.
Link to full album: https://picasaweb.google.com/107322684196653053359/CustomKayakTrailer?authuser=0&feat=directlink