Dbone,
If you could get good deminsions from someone, a local sheetmetal shop should be able to break new bedsides for you. The stake pockets, tailgate and headbaord piece should be the same as the smaller trucks and you can order them from any of the vendors. You may also be able to get the fab shop to make the curved piece as well. The running boards are a different story. I am assuming your truck was a flat bed when you got it and you want to change to the stepside bed.