There are plenty of women riders who have a problem simular to yours. There are also several cruisers that will work for you. I would say that SPORTBIKES and SPORT TOURERS are NOT in your biking future.
Yamaha 750 or 1100 Virago's -older bikes but narrow with low seat heights,
Ridley-they make some low automatic tanny bikes. All american made.
Honda, Yamaha, Kawasaki and Suzuki all make entry level cruisers that will be fine for you. The smallest Harley that you can get will be an 883 Sportster which would probably have to be dropped in order for you to manage it.
The problem with most cruisers is not seat height, it is the fact that they are 36" to 45" wide from the nose of the seat down past the floorboards. So you get a 27" seat height and nearly 48" of width you have to overcome. Welcome to the world the rest of us female bikers are trying to get the manufactors to wake up give us options over. Why should we have to buy a bike, then spend $$$ making it narrower to fit us? Isn't our money just as green as any other bikers?
I personally do not have this problem, but many of my female customers over the years have had it.
If you will be near the Colorado area this summer, sign up and attend the AMA sponsered Women in Motorcycling conference and try asking the manufactors reps why they don't design motorcycles with shorter statured people in mind (hey there are short guys as well) Then listen to the B.S. they spout back at you.