Buddy,
I have a 57 Burb and have been looking into the same projects you are.
For the IFS check out TCI(TotalCostInvolved.com) They have Mustang II fronts and 4 bar rears. They are the same as Heidt's, just a little cheaper.
As far as the rear goes a Ford Explorer rear usually has discs, posi and has identical backing plate dimensions as my 57.(60 in.) If yours is the same dimension you can also use a 67-9 camaro rear. (60 in.)
Let me know what you find out with the wood bed, I too am looking at doing that. I had planned to use the original wood as a template and do the wood strips over plywood. I think you would have to, to make it strong enough or you would have to use alot of crossbraces.
Hope this helps.
