I would be looking for an ammo motor personally...
They go like a cut cat and the SV27 esc seems to handle them ok too. I have seen up to an X445 prop used with it with pretty good speed, about 40mph in both an OM26 and electrovee hulls. That is also on 12 cells. Surface drive of course.......
Reason I recommend this is that I have a 3200kv motor in my 26in wildthing on 10 cells and am finding myself dropping prop sizes just to keep the amps down, I am currently down to an X438 and it is up around a peak of 70amps which tends to heat stuff up quite a bit, the speed is up there but the bits aren't very appreciative. The ammo motors are really good for torque.