Scott,
Do you have a Copperstate Nut and Bolt near you? They loan/rent them out. At least, when I regularly bought from them. I believe other bolt suppliers do as well.
Alibaba.com, Haydon Bolt, LeJeune Bolt, and others sell bolts and guns.
Just Google 'electric gun for twist off bolts'. You get quite a selection.
He Is In Control, Have a Great Day, Brent