My wife is Asian(Korean) and we have found thet www.evergreenseeds.com has a good selection of Melons,including smaller watermelons that would,I think,grow in your Zone.
Jim

I would try some of the following that are a little more tolerant to cooler weather: Minnesota Midgets, Schoon's Hardshell, Pride of Wisconsin,cream of Saskatchewan, & Orangeglo. Sugar Baby is also suppose to do well in NY, but I had a tough time with it last year (too many pests.)

Moon and Stars is the most beautiful watermelon you can grow. Deep green with bright orange-yellow perfectly formed circles varying in size from a grain of tapioca to fiddy cents. The leaves too are dark green and spotted. They have a kind of oak leaf shape (maybe all watermelon do, I dont know). And they are open pollinated, so you can save seed from year to year.

The caveat here is that I am not a big watermelon fan. I grown them for the rind and make pickles. I try to find enough people to take away the insides and end up composting some of it. The color inside is not very dark, but that's all I can say about it. I understand from some of the people who have accepted the insides that it was good tasting. I can only tell you that I don't think you will find a more aesthetically pleasing watermelon. Carmellia

Minnesota Midget, Golden Jenny, and Blacktail Mountain watermelon grew well in my short season last year. All from Baker Creek Heirloom seeds. The year before I got free seeds for Charentais which I successfully grew in a clay pot.

Here is a link that might be useful: Baker Creek Heirloom Seeds