I had a nice conversation with Steve @ Calmini last night. This kit is so damn cool, especially when you consider how it came to be. This design was conceived and fabricated in a very short time yet it is brilliantly executed. It's absolutely a production item, not a proof of concept. Steve already has the jigs and such built for this kit, they're just finalizing the details.

This design is readily adaptable to the (W)D21 Pathfinder/Hardbody platform too, about the only consideration of note is either the length of the radius arms or the location of the crossmember they anchor too. Steve likes this over the leaf-spring-setup kit they guinea-pigged on their Hardbody last year, even he wouldn't want to drive the HB as it is more than a couple or three hours on the road with the bump-steer issues it has. The Xterra drives so much better than the HB he's seriously considering re-doing the HB with this setup.

This kit is pretty much designed around 33" tires, but the length of the radius arms is adjustable so you can add a good 2+ inches of wheelbase if you like. Steve sees no problems with 35" tires on this axle.
Also, a D44 isn't your only choice, the radius arm brackets to the axle could easily be customized to just about any housing you like. Good news for krazy people like me that want to do something esoteric (Steve still dreams of the custom axle with an H233B third-member and D44 outers/knuckles, but knows it wouldn't have enough appeal to be worth the trouble)

I think Steve summed up this kit best when said "We've turned this Xterra into an XJ" (XJ is the Jeep Cherokee) which is a real complement, the XJ can turn from OK to bad-ass without much work at all.

Some notes and things to consider:
The kit uses the stock pitman arm. Nissan made it tough, the box is really way too far back on the frame rail and the arm is too close to it, but they found a way.
A complete Calmini IFS lift kit for the Xterra runs almost $1000.
The coilover shocks and springs for the SAS kit run about $800 alone.

Brent