Hey, I had an idea that i think you would have like. A motorized sear tripper. This engine i just sold on ebay was going to be used for it
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... %3AIT&rd=1 . Anyway you get three model 98's or pro/carbines or cheapo spider clones, cut them so their sears are exposed, and put them in a triangle config.
Then you take sporket, and cut off most of spikes so it won't catch the sear too many times you may have to cut off all but one, you'll also probally have to slope them so it won't wear the sear too bad. Then its just making a frame to put them together.
You would be able to adjust the rate of fire by putting a stop on the throttle. It could probally run of a single HPA tank on a remote, and you wouldn't have the problem of getting all the barrels to spin like with a gattling gun. With warp feeds you could have six guns, three on top and three on the bottom, maybe even eight if you put two on the side. Plus the motor would sound badass and probally scare some people. Althought all the loaders would make for a huge target, but then again if they were playing no gun hits it would also be a huge shield.