Measure the width of the rear of the FWC - in 1985 they were about 64" wide. Your 2005 Dodge is only about 61" between the tailgate posts. FWC (and presumably the other TC manufacturers) narrowed their campers in/around 1991 to accommodate the narrower truck beds.
I'm one of those people with a long bed camper on a short bed truck. You're right - they look a little goofy hanging out the back, but that isn't the worst of it. The center of gravity on the camper is a lot closer to the rear axle when you put a long bed camper on a short bed truck. That puts nearly all the added load on the rear suspension, and little on the front suspension. As a result, the truck doesn't handle as good as it should, and the rear suspension is a bit soft. It's not bad, but it could be better. The up-side is all the extra room in the camper (33% more floor space than a Hawk). We're happy with it - but could stand to put a set of airbags under the back.
"Life is meant to be enjoyed, not endured" ~someone