Sounds like a great project!
Plenty of room for piratical action in that scale.
Like the idea of a prize for the best dressed pirate.
You might consider others too, e.g. for the most successful pirate (not sure how to measure that, but options include: most treasure acquired, most ships sunk, most fearsome reputation, gets all the wenches, luckiest pirate at escaping from the jaws of defeat in the nick of time - think Cap'n Jack Sparrow); for the worst pirate - reward a man who is down on his luck; most in theme pirate, e.g. one that talks and acts the most like a pirate of the day, and inspires others to do the same, etc.
Some prizes could be larger, and some smaller, depending upon donations, or your budget for such things. Heck, even a few fake doubloons, a cardboard ship, a pirate flag, or other items might make the event memorable. The flags and doubloons can be found on eBay, or at various on-line pirate shops. Some of the coins are cheap plastic ones that look pretty nice, but others are made of metal, and fairly good replicas from the era, and some are even of that very rare, and much coveted commodity in the Caribbean, chocolate.
I imagine a few retailers or manufacturers might kick in a bit of stuff, if you are willing to give them proper billing for the event/show. Ones that come to mind are Peter Pig, Sailpower, Thoroughbred, and Old Glory/Blue Moon, etc.
Couldn't view the map on your blog. I just get a little white box with a red X in it.
Also, you might want to consider changing the font color on the left side of your blog, since the light blue text matches very well with the background sky color.
Looking forward to more info and photos, as the project progresses.