I have been hauling motorcycles on trailers for years. We make a couple of group trips to ride dirt bikes in the desert every year. Initially I used a flat bed trailer however a couple of years ago I bought a
Haulmark enclosed trailer.
What a difference! First of all what's nice is the added security when stopping overnight or at a restaurant. I haven't put any stickers on the trailer and it is white so it looks kinda generic. Then I also enjoy the weather protection. Furthermore I can use it for storage when I'm not using it for towing.
I have noticed that when I see enclosed trailers for sale on the used market they are at a considerable discount compared to new. That might be an option if you can find a used enclosed trailer. Also most trailers are used once in while and don't get very much mileage on them.
The other manufacturers of enclosed trailers that I considered are
www.paceamerican.com and
www.wellscargo.com