Before you get carried away make sure your transmission has a PTO provision, otherwise you'll have no way to run anything. Personally, I think a 350 is too small to carry much more than a compact or small car as a roll back and still drive good. Not to mention, is your wheel base long enough to accommodate a 17' or so bed? Anything less than 17-18' is pretty much useless. Your bed would have to be aluminum to save a gang of weight as well. But, there are a GANG of F350 roll backs out there - quite a few of which shouldn't be.
'99 F250 CC-SB 4x4, AFE Stage 2 intake with Pro-Guard 7, Dieselsite coolant filter, DiPricol Full gauges, AIC, On board air + Buell emergency series air horns, Striker turbo timer, Striker I module, Cyclops anti-theft module, TC lockup and 6.0 trans cooler. Powerslot Cryro'd rotors and Hawk LTS pads.