That's a first!
Wow, that's a first. I don't think I've ever had a question like this one. I did some real quick surfing across the web checking some of my favortie aftermarket shops and not only couldn't find one, I had a hard time trying to figure out what department to classify it into. Accessories, hull, storage, etc....
If I was having this problem, I think I'd probably look at my local "Lowe's" at the types of locks that are out in the market today and see what may be applicable.
The space where you reach in to pull the handle to unlock the hatch has a few inches of room on either side of the pin, so if there was some type of barrel lock that was low profile, that's what I'd try.
But to do something tacky like a lock and hasp would be out of the question. To bad you can't put something like glue on the handle to keep people out. I know if it was really bad, I'd put some type of siren in, wired to my batter with a push button switch attached to the cover, so that when they opened it, it set off a horribly loud siren of some type.
