I have thought about this before and if i had a clear garage or secure parking then i would use one. Years ago while living in Melbourne i had a pick up truck and a tradesman trailer. It was ideal, when i didnt need the extra capacity i would just take the truck but most of the time i would have the trailer.
My was lockable and very secure
http://www.trailercustoms.com.au/tradesman-trailers.php