We found a mister at Wal-Mart the other day that you wear like a fanny pack. It's called the Cool Blast by Misty Mate. It holds up to 16oz. of water and it uses a pump instead of batteries. The tank is insulated to help keep the water cold and has a 3ft cord with alligator clip so you can attach it to your shirt or what not and it weighs around 2lbs.
Go to Misty Mate dot com and click on new items. It the third one in the second row. The website sells them for $54.99 but we got ours for $13 and change at
Walmart in the Fan and Air Conditioner section.
Gave it a test run and it worked like a charm. I even caught DW using it to mist her plants.

Can't wait to use it when we get to the World in June.