Jamvan,
Your only real option for an enclosed trailer, coupled with your current tow vehicle is going to be a Trailex item:
http://www.trailex.com/buycat.cfm?cat_id=93
Be prepared to cough up at least $14,000 for the privilege of buying one that is enclosed.............Shoot me off a private message, and I'll clue you in to the 20 foot enclosed trailer I have here in Rockaway.....................You could go with something smaller in length, but you really don't want to.............
Bill S.