Who wouldnt. Problem is, a real one would probably run you from $30000-250000. And you'd have to have ATF approval and all kinds of shit. Then pay $20/second to shoot it.
You can get one of those guns that shoots metal BBs for $4-8k, without the paper hassle. Hell, you could use one of these as a self-defense weapon. That'd be crazy shit to just shred a buglar to pieces with a BB gun.
A BB is a small metal ball (i believe 4.5mm/.177cal). Fired with CO2 or hooked up to portable air compressor, its going to be flying pretty fast. I'm sure they'd penetrate the skin, but probably not bone. You can see videos here: http://pipersprecisionproducts.com/videos.htm
There's a shooting range in Indiana where you can rent a real GE Minigun, flamme thrower, pre-1900 Gatling gun and many other toys. Pricing is terrific. One burst with the flamme thrower is like 75$ or 100$ if you want napalm.