How about the KHS Cidi 8? May not work due to limited sizes, but then again it might....

I think I may have just found a WSD step through in a 19" size- the Trek Cocoa. It's only a 3spd, but if you find that won't be enough gears, you might be able to go upgrade to a 5, 7, or 8spd IGH within the upper limits of your budget.