OK, so I did it. Towed it about 8 hours so far.
I wanted to do a tire tail, and cut one of the louvers, but found that I would have had to cut the two small holders that the tow eye cover snaps into, so with hindsight, there is no cutting required. (didn't want to pull the whole grill) I got a 2 1/2" bolt with lock washer to fit into the tow eye mount and welded it onto 1 1/2" black pipe, then a small channel for the ball. I screwed it in tight and marked it for the welder, but he put it together upside down, so we grabbed a rubber washer from our shop and that shimmed it so we could get it tight and upright, and it worked ok on the trip.
We finished the trailer (3 1/2' x 4' Harbor Freight, 12" wheels) later than planned Friday, and when I slid the wheels/tires on, the tires and not the wheels touched the pipe in the center, so I hit the road for the track. As you can see the wheels did touch, the pipe took some paint off, and so I now have them mounted as in the picture. I was planning to pick up some touchup paint, but my warehouse guy put some black marker on them and said it covered real well. The horizontal tube I got was a little too thin on the wall thickness (is about 1/16"), and one side bent down slightly. So I went to a Home Depot near the track and got a piece of steel pipe and slide it inside the tube, so that any sagging will be limited. The holes in the stock wheels are small, so I needed to use 1 1/2" pvc (which is actually 1.6" id, 1.9" od) to work, so I went to a steel fabricator and got a steel tube (not pipe) in 1 1/2" od (regular steel pipe will not work.) so I could slide the 1.5" pvc over it. The Enkei have a slightly larger hole than the stock wheels, but not large enough for 2" pvc (the 2" just slides over the 1.5") to fit into, so I just used the 1.5 pvc and it worked ok, but before my next track trip I want to get a bungee, etc, to hold them straight up and down. My warehouse guy will be painting the tubing/angle assembly black this week. And I might try to build a small platform between the tool box and tires for a couple gas cans. I have about a 9" piece of 2" pvc on the inside then the wheels, then a 1.5" to 3" pvc reducer. I drilled through the pvc and the steel tube for a locking hole. On the stock wheels, I used the reducer plus a short piece of 2"pvc on the outside. Depending on what wheels you have, you can just cut pieces of 2" pvc the right length for the reducer to be tight against the wheel and held with the lock. One thing on the trailer, you have to clean the wheel bearings and pack with a good grease, we used synthetic. After feeling it out, I ran with the cruise on at 75, no problem. Hubs stayed cool. Am out to time now, will plan to post some pics later.