Are you looking for a conversion for function or for the purpose of replicating the original RHD? Was the original a drive system which drove the left unit from the right side?
If I were going to do it I would re-configure some of the structure behind the dash first. Second if I were going through this kind of trouble I would look at steering raqs. The BUMP STEER in a Pantera comes from the steering rack pivot joints being at the wrong width. If you could find the right width or modify the existing raq one could nearly eliminate bump steer.
There are a few things behind the dash a little different left right but it wouldn't be to hard to swap most of the existing metal.
The dash itself would be different.