I was told when I bought my enclosed trailer that it was 22 feet and that turns out to be perfect for my needs(I've never actually measured it). Before that I did the open trailer and slept either in the back of the truck or motel which got pricey. We have since turned the trailer into somewhat of a toy hauler with a couch/bed, tv, linoleum floor and family portraits. This actually works good for us with plenty of room for the car, scooter, rolling toolbox, BBQ and stove, and assorted tools, spares and jacks.
I was initially concerned about towing and storing but it fits perfect in my rv parking with room still for my parts car and my Tundra tows it just fine although gas mileage isn't great. Packed for local races I average around 10/11 mpg but for nationals we got 12.3 round trip including climbing over the sierras. The loaded trailer weighed 7100lbs.
Now that I'm used to the enclosed trailer I don't think I could go back . It's a weather tight hangout and garage in one, not to mention storage for the car and stuff at home. Paired with our Yamaha inverter, it's very relaxing to sit under the awning sharing a bottle of wine with the big dog and lil kat under the awning with the lights hanging from it and then retiring inside to watch X files dvd's with popcorn!