The bellhousing is the least of your worries, The whole cooling system has to be modded so that it's similar to a pajero, otherwise you'll end up with an air lock in the front (highest point)and it will cook, Unless you've studied a pajero cooling system , then you won't know.
The idea of a flange sitting between the sump and the block is a good idea depending on the motor. I know a guy who modded a stockcar that way , I think it was a ford straight 6 , it was done for both strength, reliability and ease of pulling the motor. He built a thick flange to go between the sump and block, That had pipes welded to it which you slip the engine mount bolts into. Tricky though with a Mitsi as you've got the front & rear curved bits for the crank.
Steve