Probably not a reasonable thing to do if you have to hire it done but I ran into a fellow a couple of years ago that loved the Ford Super Duties but hated the 6.0. He had converted 2 and was gathering parts to do a third. He drops Cummins in them with a kit he said cost around $3k. Of course you have to find the engine to go with the kit. Said it makes the best truck on the market.
When I was looking I decided I wanted a 7.3 for reliability and spent some time to find just the combination I wanted, a 2000 F250 6speed. Did have problems when a clutch spring let loose and jammed the clutch but been happy in general with the truck. I started looking for what I bought when I discovered that standard cab, 2WD, 6speed SD were not much more than the equivalent gas truck,not many made not many people want them. Of course diesel was cheaper than gas then. Since I don't really need this much power the majority of the time I would probably go gas today.