This is, IMO, the best and most functional "kit" out there. Although it's not a "kit" per se', aside from the front suspension.
http://www.thenissanpath.com/viewtopic.php?t=2558
It will be pricey. About 2200 -2500$ for parts, depends on if you get the external reservoir shocks or not. And of course with all that suspension, you wont want to keep the stock tires, so there goes several more hundred. But with disconnected sway bars, this gives the most travel and articulation and most capability offroad, as far as suspension is concerned.
OME for the rear springs:
http://www.rocky-road.com/pathfindersus.html
PRG for all the other stuff (Front UCA's, coilovers and rear shocks)
www.prgproducts.com
Call Greg for your set-up, he can give you the best advice for what you're after, such as spring rates, etc. You can even piece together budget kit from PRG with spacers and such that will probably only be half the priced I mentioned up above.
And also for a series of everything mixed in, which gives you the ability to REALLY play around with set-ups:
www.4x4parts.com