I think it would work fine.
Splash guards could easily protect the turbocharger from debris and water.
It would be laggy as all hell though.

It would work good with a small turbo on the engine, and a big one without VVT after the DPF. That way these units would sound awesome .

Personally I realize that there is a reason for everything being done the way it is, but I would have loved to see all the aftertreatment junk under the truck, leaving the engine bay open and easy to access.

There is a lot of room under the cab.