Light weight vehicle doesn't need the 600#'s front axle (D60) underneath it to survive. Check out Tri-County's Jeep which runs under a 4cyl engine, D30 up front (strengthen in comparison to D44) and D44 out back (strengthed in comparison to D60).
http://www.tricountygear.com/specs.htm There was an article in a mag about what they did, thinking it was the JP mag. They run this vehicle in the rock challenges on 37's.
Their concept on axles would work out easily for you on your Tracker. Get the early non-wide track Jeep axles, upgrade in gears and lockers, and your set on the axles from breakage.
What Tri did was to machine the ARB to accept the larger side gear. This increased the axle diameter and thus the strength. For the front, they also used the stronger u-joints in the D44 sized axles. To add, with the smaller diffs, they have better ground clearance in comparison to those running D60s.