So you want a lot of air, huh?  This is about as big as you can get without getting a separate trailer to haul your tank in!  12 gallons of capacity, with eight 1/2" ports and two mounting feet for easy installation.  And of course, it's coated inside and out for protection from corrosion.

Dimensions: 44" long, 12.5" round, with two feet that extend 2" from the bottom of the tank.