What is the reason you are needing a rebuild? As long as the block and head isnt cracked, a rebuild is the cheapest solution if you are willing to turn the wrenches. You can even call your local machine shop and see if they can qoute you a price on a rebuild. At a minimum, see if they will do the machine work on it( Bore,grind crank, valve job, ect...) Some of the diesels used cylinder liners so that would eliminate the need for boring.
The reason the dealer is suggesting a reman, is because that is what they do. Shops seldom rebuild engines anymore as it is very time consuming and costly. Faster for them to just drop in a reman and go.
I suggest you belly up to the NH parts counter and start pricing the parts for a rebuild and go from there. It may not need everything, but no way to know if its still in the machine.
