building a single axle dump. conventional box or contractor?

[MOE]

I picked up an international 8600 single axle over the road truck. I'm going to put a dump bed on it this winter. I'm a bit torn between a 10' bed with 30" sides. It will fit perfectly with the current wheelbase,(154"). The other thought is to stretch the frame and put a 14' contractor bed on it. It will be used to tow my tag trailer more than haul. It will haul some dirt, crushed granite, firewood, and a few large round bales when I haul hay with my tag trailer. I like the simplicity of putting a 10' bed on with no frame work but the low sides of the contractor bed seems like it would be nice too. Any thoughts on practicality or costs?