My wife (5') started with a CB 400 we chopped the seat on that. But now has a Monster 600. Dropped the forks 1" and lowered the rear ride height wishbone thing (old style Monster) by one inch. Bike is much lower now, the handling is ok other than it grounds out a bit soon but it is not a problem for her. Once she has more confidence and strts grinding the pegs then riding a taller bike won't be an issue.
Mike