What Derrick said. I can't see any benefit whatsoever in doing this on a 14' SIB, just negatives, such as;
More total weight. Not only the extra weight of the unit but also of a battery that would probably not be needed otherwise.
That additional weight would be concentrated at the stern in addition to the sternward relocation of the motor itself. The planing and handling charactersics of the boat (both with oncoming and following seas) would be awful.
A huge hassle if ever wish to fold the SIB.
I'd simply do some trials to see what fixed trim setting is most efficient for that boat with the motor on the transom as it should be, and stay with that. Simply be sure that when you load cargo you pay attention to weight distribution.