Here is another thread where we discussed this last year. I am still running a short bed TC on my long bed Chevy. Still pleased with how well it works and the additional storage space is great. On my Lance 845, there is no external storage space on it, so the box space is sure nice to have.
It does look a bit dorky I have to admit, but the idea works fine. The center of gravity of the camper stays the same in relationship to the rear axle so no difference in that. I was running the same TC on a short bed Dodge Cummins with a GVW or 9,200 lbs and the current Chevy has a GVW of 13,000 lbs. So this is the first of our 5 TCs we have owned that isn't greatly overloading the truck.
I still need to go talk to one of the fiberglass boat shops in the area to see what they would build me a nicer looking box and charge.
http://www.rv.net/forum/index.cfm/fuseaction/search/parms/sw%7Bshort%20bed%20TC%20on%20long%20bed%20truck%7D%7Ckm%7Bexact%7D%7Ckl%7Bm%7D%7Cfm%7B27%7D%7Cpd%7B365%7D%7Cma%7B%7D/sr/1.cfm