[100 TD]

I don't think you would need a LHD, simply we are talking the engine here, it is only made in one format, the transmission and transfer are only made in one format, just the linkages/selectors are different. Remember the fuse box/battery on your LHD is in the same place as a RHD, air cleaner in same place, the only things they swap are the steering column/dash/brake master cylinder/ wiper motor etc, not the engine components. I thought there was a difference in the chassis on the HDJ100 compared to to the UZJ100, but maybe I am thinking of the 105 which has the 80 series RFS.
Spill valve controller/ radiator? should be OK, fuel filter/pump and piping would be good, but not essential, I think the Evap pipes could be used sucessfully for diesel return pipes etc. Exhaust cat etc may be available from other toyota trucks or just aftermarket.
The ECU would be the biggest hurdle, even though it may plug straight in to the existing harness, some problems may take a bit of work. Definetly doable I expect, I think the UAE are LHD aren't they? If so then LHD diesels are standard and fit OK