GTurboed and intercooled 1HD-T with a H151 behind it - good power and torque and gets mid teen litres/100 km towing. I may be biased though...
As an 80 diesel owner I am offering another biased opinion. The HDJ80 has a train weight of 7.5 tons! So that puts some perspective on it. Both the 12 valve and the 24 valve versions are pretty bulletproof (but check the BEB's on the 12 valve). You get low lugging power with a diesel, I can hit the local 500 metre climb at the bottom at 90 MPH in 5th and not change gear and still hold that speed. You get no complex electronics, common problems with engine swaps are the electric stuff early diesels are easy peasy (or buy one already done), and when not towing I easy get 27 - 29 MPG (imp gallon). With the roof rack loaded with one of the spares and a RTT, fridge in the back and camping gear, food, and other stuff, the mileage drops to around 24 - 26? I do tend to drive slower when loaded up but, it will keep going, even with no mechanical engine cooling fan (all electric) it never gets too hot. Want more power, leave the stock turbo in their and tweak the pump, want even more then fit the intercooler kit but me, I love it as it is. And the reliability of diesel motors has been proven with out doubt, just think, opening the bonnet once a year to service it. Oil and three filters and your done, forget plugs, leads, head gaskets, OBD light at inspection time. Initial outlay is higher but, bring your better mileage and lower servicing costs to the table and you will be the winner.
I also noted your comment about others doing the swap (engine or even car), they have seen the light, of course there will always be the nay sayers

, there was when I done the 24 to 12volt starter conversion, it worked and is now copied, and I saw the same with the electric engine cooling fan, it will never work was the cry but I did it, and not only does it work, keeping the engine cool in one of Spain's hottest summers on record, it has improved the AC efficiency as well, just another benefit. All information and facts and figures in
My LC 80 thread.
Just my 2 euros worth.
regards
Dave