Here's a list of seat heights as a start:
Total Motorcycle - Beginner's Guide to Motorcycling - Section 2.5
It's 2005/2006 models, but they shouldn't have changed too much in the last few years. It's H-D heavy at the top of the page, but that's because cruisers have a lot of "low" versions, the Ninja 500 is halfway down the page. The Katana is close behind and most of the sportbikes are in the 30 inch range.
You can also lower some adjustable-suspension bikes and you can always have a suspension lowered a bit for a price. There are also seat options (not many for sport bikes, though) that can save an inch, but you'll probably regret it.