Finding shocks to fit the rear should not be too difficult. According to the Rancho fit guide
http://www.gorancho.com/products/applications.stm with 2.5" lift in the rear a RS5116 will fit. This is the same dimensions as a stock rear shock for a 1980-96 F-150 (1/2 ton) 4WD. I know Gabriel makes Hi-Jackers for that application because that's what I run on the back of my YJ. Only issue is whether there is any interference from the wider body on the air shocks. BTW air shocks on the back are great for towing.
If you cross reference through the spec guides looking at length & eye type you may be able to come up with a shock that is a stock rear fitment for a truck that will fit up front on an X. My YJ has Bronco rear shocks up front.
I can get 2" extra lift if needed. It puts extra strain on the shock mounts though so I wouldn't recommend running a lot of pressure for very long.