I have air ride on the rear of mine. Its pretty cool to drop the back of the truck 6-8" when you want to. I think you could run a suspension like I have on a tandem rear with one facing frontward and one in the traditional backward position. Your axles may end up a bit farther apart. As far as putting a rear air ride on the front, it looks to me like one limitation may be the amount of frame in front of the axle-I'd have to measure. Track bar-oil pan clearance issues will be another issue-if your suspension requires a track bar. There are a variety of air ride setups out there, and the one Im using is more out of easy availability than my first choice. Theres one on here with a Freightliner setup that looks ideal to me.