Short of doing a solid axle swap your best bet is doing a combination lift (suspension and body lift). Like Mike, I also recommend getting the Sway-Away torsion bars to lift the front end about 2" and longer shackles to lift the rear about 2". Then I would add a 2" body lift. This will net you about 4" of total lift. I would also recommend getting some 4.62 gears out of a Montero so you can run 33-35" tires with this setup. If you're somewhat handy with tools I think you could do all this (tires excluded) for $500-600. The CV's on these truck are pretty stout and have been proven to with stand the punishment of running 35" tires.
By only cranking the torsion bars 2" you avoid having to replace the drive shafts which can get pricey. If you have any other questions feel free to ask.
Here is my pickup with 14" lift via an SAS
