I suggest using one of the Chevy diesels prior to the Duramax. 6.2/6.5/6.5T. They were made for chevy to their specs. The Ford and Dodge diesels were pretty much carry-overs from their Navistar and Cummins production, so they required SAE transmissions to go behind them. I suggest staying away from the Duramax since it is installed to a Chevy truck like Brain Cancer in a frontal lobe. You can't really separate it without damaging both
The Chevy 6.2/6.5 family uses standard motor mounts and tranny bolt patterns, so they are bolt-ups.
Probably the wiser choice of the chevy diesel family I listed above is the old 6.2. They were pretty bulletproof and entirely mechanical. The newer 6.5 and 6.5T were electronically controlled. Not that its a bad thing, but its a much tougher swap with more to potentially go wrong. The trannys used behind the later 6.5Ts were also controlled by the computer, so using a 700r4 would possibly confuse the computer further. I might also consider getting a whole kit and caboodle 6.5T and 4L80E tranny. The benefits are that performance upgrades can be had both electronically and mechanically (an easy 100hp can be had with just a chip) and the tranny will be able to handle the torque you give it. If you're really going to stick with the 700, the 6.2 is probably the wiser choice.
The 6.2 can be rebuilt with a little more displacement and aftermarket or GM turbos can be added. Standard mechanical upgrades can be applied like fuel injectors, fuel pressure increases, compression changes, propane. It will never be a screamer like a new Powerstroke, but it will be a good torquey engine with tons of life to it.
Swap requirements would probably include an aluminum radiator (since they're a little more stable with the coolant additives diesels require), bigger fuel lines along with the matching fuel pump, and a huge exhaust. For reliability's sake I would go with two batteries and some huge cable. The amp draw it takes to crank over one of those things is pretty stiff.
You might also consider some sound deadening. Dynamat on the metal panels like the firewall and under the hood help tons, and so does carpet padding glued to firewalls and other low-heat places.