So, it's not really what you're asking about but... there are a lot of blackberries growing around here in late summer, so I made a blackberry vodka last year. Put a bunch of blackberries in a big bowl, mashed them up with a potato masher, filled a BIG jar (can be bought with canning supplies) about 1/2 way with this mash, filled the rest of the jar with vodka, let it sit for 2-4 weeks (shaking it occasionally), poured it through a few layers of cheesecloth a couple of times, then drank! Great stuff, can't wait for the blackberries to come on. I also have a bunch of plum trees here, and did the same thing with them soaked in brandy - another good drink.

I imagine you could do the same sort of thing with watermelon - chop it up, soak it in the vodka for a while, shake it once in a while, strain it, and drink. Not the same as vodka soaks pieces of watermelon that you'd eat, but sounds like it might be a good drink.

By mashing the fruit up you are getting more than just slightly flavored vodka - you're getting a lot of the fruit juice in there too. It tastes great though, and the proof still seems fairly high.

Anyway, slightly OT, but thought I'd share.