You should get in touch with High Performance Paintball in Harrisonville, MO. They're located in the city park in Harrisonville, and on the web at www.highperformancepaintball.com
They have a pro shop, rental markers, 3000 and 4500 air - also airball and a couple of woodsball fields.
Sounds like your parks and rec department could ask the field or the city of Harrisonville for suggestions. I played a tournament there last weekend and it was awesome.
(Oh, and I moved to Missouri from Utah a couple of months ago, which is why I happened to be wandering through the West forums)