Des, I doubt you would find one. They are in LS430 and SC430 (I think that is the designation for the ugly convertible with waste bin wheels).
I doubt more than 2,000 of both have been sold. You would be looking for a write-off which would not be cheap.
You would also be in unknown area with how it all works and wires up as no one has looked at them.
You could get an engine out of the States but I think it would need to be a Ca car.