I have been running a pair of viair extreme duty pumps mounted under the hood of my jeep for over 2.5 years. No concerns with it so far. The kit came with a 3 gallon tank that was mounted in front of the rear axle. It tucks nicely out of harms way.
Also, to solve my M416 being left at camp with no air, I removed 2 air pumps from Ford expeditions air ride system's. They got plumbed together and crammed into a large ammo can. The hose and power wire fit nice too!
John is right about the huge power needed for the pump. Thats why the ammo can and longer power wire with battery clips were needed.
My buddy gave me an idea of just going from my jeeps system to the trailer with a quick disconnect hose like the semi trucks use. I will try it when/if the ammo can gives out.
Oh yea....i used my jeeps air to build my barn last year too! Nail guns are a good thing