I was thinking it might be an option to get one of these and kind of gutting it -removing all of the extra cabinetry. They claim dry weight of 1233 lbs. I wonder what you could get it down to if you removed all the overhead cabinets, and the big passenger side cabinet at the back. They are definitely cheaper than a FWC.
http://www.truckcampermagazine.com/camper-reviews/2014-palomino-ss-600-backpack-edition-review/
http://www.truckcampermagazine.com/camper-reviews/2014-palomino-ss-600-backpack-edition-review/