I'd say don't, but if you have to, lower them on some airbags so you could lift it was well. Cut out the wheelwells, lower it on 33's and with the touch of a button lift it into a monster. Or ruin it by lowering it. Im not trying to bash, but if you must, make it lookgood. Theres nothing worse than a lowered jeep that looks like shit. Post pics when it goes down.
I see no reson you couldn't pull leafs from the rear pack, or better yet get some custom leafs made. Could also go with some lift springs and then go spring under? Fronts easier, cut some coils out or custom coils. Years ago TRW used to list spring rates, installed heights, and spring diameter for all of their springs. With all the computers now in the parts store may be harder to get this info though.
I doubt you'll find much support here for lowering your Jeep but hey man it's your Jeep, make it into what you like. But most peole here lift so there is little experience (and desire) going the other way.
Driving a jeep instead of a car gives you horrible gas mileage. What would be the point of having a jeep if it's lowered? Why not get a car that would get double the gas mileage, and handle WAY better than a lowered anything? If I didn't need a truck to tow with and go camping in I certainly would be driving a car...