Inventgeek has released their Paintball Turret Plans so that you can make your very own! The kit is available here at Ponoko. Sounds like you may be able to wait a bit and purchase a cheaper version direct from Jared at Inventgeek though.

"Due to an overwhelming interest, we now have a full kit available from Ponoko.com. This kit includes all the parts you will need to assemble the main frame of the turret project. The only down side is this is a band aid until we get some manufacturing in place. Ponoko is very expensive for the service they provide. We hope to have a cost effective alternative soon."