[edgeleycanuck]

Very interesting, this is something a little different, I will enjoy watching. Not sure what your plans are for actual bed length but I'll throw in my 2 cents.
I also started with a 9 foot box, I shortened it to accept the unaltered floor I salvaged from a 2000chev extended cab pickup(6.5 foot bed), it ended up being about 1 inch longer than an original 1/2 ton wheelbase. In my opinion these trucks are short and I wouldn't want to be any shorter wheelbase base than the original 1/2 ton. I also used a rotating laser to get measurements from a level original frame, worked great.