Going against TBN wisdom... I use a single axle car trailer with rails and open center and hydraulic brake. The rails are 10' long and the trailer is rated for 3,500 pounds. It is commercial trailer built for SCCA events back in the 60's.
I've towed about 1500 miles with this set-up... mostly behind a Ford Excursion.
The one time I was flagged to go the weigh station... officer wanted to know if I was commercial and then looked me over. Needed to see if I was properly chained down and secure.
The trailer and load came in at 3420...
He then asked me if I could do any real work with such a little tractor and I told him you bet and he sent me on my way...
I like being able to move my trailer by hand and the 10 ply bias ply tires seem to last forever... don't have anywhere near the tire life with my double axle enclosed car hauler and the double axle trailer is north of 3000 pounds empty.