Here's the combination I would recommend:
1. F350 DRW 4x4 diesel or gas, you don't need 1000ft-lbs of torque to move a truck camper so a 7.3L diesel would be fine.
2. Flat bed.
3. 9.5' floor length camper. A camper this size will be light enough that you can load up elsewhere.
4. Aluminum tool boxes to fill in the spaces under the camper wings. The kind you see mounted to the bed rails on contractor's pickup trucks.
5. Aluminum tool boxes hung under the bed if you need additional storage and can spare the clearance. Maybe low profile to maximize clearance.