The quick answer is don't frame swap, do a solid axle swap (SAS) in the front. The rear is easy to lift, shackles or add a leaf to the spring. If you want more like 5-6 inches move the springs on top of the axles. Pull the IFS and put a straight axle under the front at whatever height you want.
A frame swap sounds easier but there is a LOT of fabrication work that would be needed, not to mention getting all of the controls and drivetrain working in the LUV body.
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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)
MEPR: Man, my 4x4 makes all other LUVs look good