Ive acctually been pondering building one of these trucks, been doing alot of research lately. You dont have to spend crazy money if you look around you can find a 03-04 int, ford, chevy for under 10 grand. now there gona be 2wheel drive and be reg cab. and have a long frame. but if your good with a welder and body work you can take a pickup ext cab (or quad cab) from a junk yard and graft it onto the truck. Then get a nice dually bed and shorten the rear frame accordingly and move the rear axle forward and have the drive shaft shortened.
Im currently looking for a 03-04 Int box truck under the 26K gvw
I wana do that front cab and graft in some escalade headlights and do a "Super Escalade HD" The wife said ok my only problem is my garage is not big enough!!!
But in all reality if you did a reg cab and dually bed you could build one for bout 10-12K
Note avoid high mileage cat diesels they need complete overhauls bout every 200-250K and can run over 3K.