I don't have the truck yet, just asking in an attempt to gain some info for the eventual purchase some 3-5 years from now.
I think the 450/550 with a 200.2" wheelbase from Ford is the best way to go for the ultimate goal of having a custom length XP Camper mounted to a flat deck. The truck will hold the weight with ease, and still have plenty of GCVW left over for a trailer or excess gear/extended fuel tanks etc. etc...
And with the relatively light load on a medium-duty package, the whole package should provide a higher level of reliability.
Why I asked my original question about the cost of changing over a manual to auto transmission is that the manuals seem to VASTLY outnumber the automatics. The manuals seem less expensive than the autos as well, so why not buy a manual model and pay for a brand/new reman'ed and beefed up tranny that I could be very confident with? It seems like pretty much all auto transmissions seem to be a bit weak behind diesel engines, no matter what make or model.
Another "ideal mod" would be to swap in a reman'ed 6BT Cummins, and if doing that, why not get the tranny at the same time?
I think what I will end up doing is buy an auto truck, with the stock engine, have the XP mounted to it and drive it like that within N. America, and if I have any serious failures, I could get the engine and tranny swap done then. Get the built-up engine and tranny sorted out properly before taking the vehicle out of Canada or the U.S.
Ok, there's a bunch of ramblings from me, plenty for tonight.