I think you'd struggle with the width - hence the bench seat being the size it is. With the handbrake and gearstick being where they are, I'd think you'd have difficulty. What might be worth considering would be reupholstering the bench seat - makes a world of difference! And there's at least one chap on the forum who does some excellent work (look up Superstich) T:
I am in the middle of the same project. I fitted Alfa seats in place of bench and drivers. I then used the frame from the original bench and cut it down (narrowed) to fill space. Have all frame together now need to get it re-trimmed. A bit of messing and welding but it can be done. Will post some pics when I get it sorted.