I just bought one of these:
40-1/2" x 48" Small Utility Trailer - 1090 Lb. Cargo Capacity
$240, can't argue about the price. I aim to pull it behind my VW Passat TDI, which is rated to pull 1000 lbs. It is 40" wide in the bed with the fenders adding about another 12 inches, so it fits behind the car. Nice thing, in Oregon there is no registration for trailers this small.
I have a question though. Assuming I make some effort to put some clean sides on it, and a top that tapers down from the level of the trunk, with a 12 degree slope to the back, and a flat bottom, is it likely I will get better mileage with trailer attached than driving the car without a trailer? I'm thinking the aerodynamics will be better but the rolling resistance worse...
I want the top half removable so I can put my motorcycle in there at times (yes I know I have to extend the bed for that). I know that will not be very good aerodynamically.