My experience is somewhat limited with newer non-Isuzus, but I do like the truck-based Rodeo with that sexy DI motor. Getting free financing from Isuzu is also attractive... you might also consider roof-rack flexibility for all of your various strap-on hobbies <img src="/forums/images/graemlins/pfft.gif" alt="" /> -- that alone would discount the Xterra, with its for-looks and otherwise-in-the-way fat-tube rack (gotta love how the moonroof and rack designers apparently must NEVER have talked to each other!). I think the Rodeo wins hand-down for USABLE interior space, even without a rack.

Miscellaneous thoughts:
* I was kind of surprised to see the Xterra so much in the lad for ground clearance -- do they measure differently than everyone else, or is that just a benefit of the larger stock tires?
* I suspect that your Rodeo headrests will wind up permanently uninstalled and stored in a box in the garage.
* I like black plastic on the inside for easy cleaning and repair -- a quick spritz with a protectant really dresses it up! I'm *NOT* a fan of fabric panels for the inverse reasons, and I'd almost rather have vinyl seats for similar reasons. Though perhaps in Arizona's direct sunlight, that might get *sizzle* a bit uncomfortable. If I had black plastic on the dash and black leather on the seats, I'd be in hog heaven. The only thing better might be my lovely wife in (small bits of) black leather beside me, but I digress. <img src="/forums/images/graemlins/rodent.gif" alt="" />
* That rear Dana 44 with disks is a nice axle by any measure, and is easy to upgrade when the time comes.
* White is a cool base color that you can customize if you want with subtle cues or custom stripes -- also easiest of all colors to match if you need to touch-up. Tends to hide small ripples, as well.
* I detest the huge clamshell hatches that have come into fashion. You damn near NEED an electric motor to swing that much glass, metal, and plastic -- tough to do with a bag of groceries in one arm. I much prefer the ambulance-style barn doors, but having a tailgate, flip-up window isn't a bad solution either. The 4-Runner's electric rear glass is awful nice, though I'm told it is a somewhat common point of failure.
* I did some backseat-time in a Liberty, and it SUCKED. No room for 6'1" me -- tight on my knees, tight on my hips, tight on my shoulders. On the flip side, when I finally elbowed the fellow out of the shotgun seat, that fit quite well.
* I gotta admit that the Nissan supercharger excites me, too bad that it is strapped atop such a lame motor. <img src="/forums/images/graemlins/frown.gif" alt="" /> Could you imagine that blower on the Rodeo? <img src="/forums/images/graemlins/smile.gif" alt="" />
* BTW, if you buy a Liberty or a Rodeo, I'll buy you a first-aid kit and even offer to hammer a 'bump' for it into the trailgate. <img src="/forums/images/graemlins/pfft.gif" alt="" />
* A Nissan XT I was in rode completely differently with a small lift and larger tires... it was WAY better than stock IMHO, though ride compliance was provided at cost to body sway.

Kudos, BTW, for your consistent approach to testing, over the same road, with the same conditions. Most folks compare only loosely, and let their first impressions drive their purchase. I can't help but think that your approach will make you more confident in a lasting decision.

I'll freely admit that I'm a bit biased in favor of Isuzus, so take this all with the requisite grains of salt.

Randii