I'm 5'5"/120lbs and I own and ride an unmodified and unlowered 500R, with both feet firmly on the ground. My ZX6R is lowered about 2.5 inches. Absolutely NO problems whatsoever. Both bikes have about the same weight, the ZX gas tank is a bit wider,and that makes her feel bulky. Each bike handles completely different from the other, but once you know how to position yourself best on the seat, balancing them is easy for a short (weak...hahaha...) woman..
500Rs are still available, in fact the dealership here in town has a brand new one, that for some reason nobody wanted. They are asking about $3000 for it, and it has never left the showroom. Just look around, some stores might have taken one in as trade, and they are just hiding it, because they are making more money on new sales.
Both of my current bikes are fun as hell (so was my Harley, but that money went into the ZX...). I got the 500R about 4 years ago as my beginner bike, and I put 17k miles on it. The ZX6 moved in 15 months ago, and she's been carrying me for 12k miles since then. In fact, I always try out different stuff on each bike,and I never stopped learning.
And for the record: No speeding tickets...and no attempts to 'kill myself', regardless of what the relatives are bitching about....
Take plenty of time, make your choice, always wear your gear, and enjoy your new bike!