Forget about IFS, think FIS.  That's right, FULLY Independent Suspension.
Ford 9-Inch Diffs front and rear, in an Anvil configuration, Dual a-arms front and rear, with coils, obviously locked, both ends (I'm liking the e-lockers that Nate & Heather have).  Slightly longer wheelbase than a kick.  Serious CV axles all the way around, and IDENTICAL axles.  Dual 2:1 or maybe a 2:1 and a 3:1 transfer case...  And the rest stock Sidekick.  Well, maybe Corbeau Seats, and a nuclear stereo...  Put that bad boy on 37's, maybe...
Dang, I gotta learn to WELD!