Common lumber and sheathing is 8 feet long, so having a 6.5 foot bed means not having to flag the lumber while you're hauling it. Also I can't imagine fitting a gas generator, 5-gallon can, gas compressor, saws, nailguns, hardware, and nails all in the back of that 4-foot bed. When I was framing people would fill up their S-10s with the gear.