when you lift your truck it will alter the driving characteristics, you will have a higher centre of gravity and it will drive nothing like it does now. Even if you fit big wheels and skinny tyres it will not handle the same and if you try to, you will get caught out.
Why not fit bigger tyres on 15" rims, that will fit your arches. Many of us run MT's or AT's all the time and as long as you drive within their limits, they are fine.
You have a Jeep not a Caterham 7 ROFL