Not sure I understand what's really broken. Is that it in the link? If so, I can't imagine that costing more than $500 to repair the front drivetrain and suspension (ignoring any body work). In fact, you'd do as much work changing it to 2wd than you would simply repairing it! There's probably a good amount of labor factored into that price no doubt, but the parts themselves are relatively cheap and easy to replace.
But, 4wd is a system, not a part. You got hit up front; I can't see any reason the transfer case (the heart of any 4wd system) would fail in that collision. I do see that the shifter is in the 4L position (or beyond it?). What's that about? Hope those guys didn't tell you it was broken because they didn't press down on the lever to move it from 4L to 4H.
The front axle is bolted to a subframe, and judging by those pics, I'd expect the axle and subframe to be unscathed. The front suspension and steering components would have absorbed it.
Here's how I see it:
Transverse link: If you mean lower control arm, it's $45 from rockauto.com. Includes bushings. You'd need a new balljoint ($8-$60...good ones start at $30). If hardware needs replacing, it's available from Nissan for cheap. I can provide part numbers.
Frame work: well, there's no frame, but instead a unibody. The subframe holds all the drivetrain, steering, and suspension components. In order for that to be damaged, you'd have to have some serious damage to the body, and I really don't see that. I mean, the wheels look almost perfectly aligned still!
Stabilizer bar: there's one on eBay for $55 bucks...says it's for a 96-99, but should fit anything 96-04. It's not even critical for driving.
I would expect to change out the lower control arm, ball joint, and steering tie rods for safe measure. These, if anything, will bend on impact. Some guy is selling a kit to freshen up your entire front end for $65 (
http://www.ebay.com/itm/181775312999), which I'd recommend anyway. You'd probably need a new strut ($60); most of the hardware and coil spring should be re-usable. The CV ($45-$60) should be inspected and replaced...but it can also be rebuilt.
Seriously, I'd have that in my garage and disassembled already! Not sure you level of skill, but nothing here requires more than decent mechanic's set of wrenches and sockets, and maybe a free tool rental from your local auto parts store. This, of course, depends on the severity of damage unseen.
Another option is that you completely pull the front subframe and put in a new (used) one! It's literally 8 bolts (well, if you don't count the 6 on the struts, 4 on the driveshaft, 3 on the steering link, and some steering hoses...let's just say I've disconnected my subframe and changed out my entire suspension).
But let's talk 2wd so you can weigh your options:
--puling the front driveshaft is free. But, you'll still likely need to do all the stuff above!
--if the axle is bad, you can leave it in place, or pull it. I bought 2 front axles over the past month for <$150/ea locally...they are everywhere. (I'm doing a gear sway and locker install very soon...if you need a 4.363 axle, which your PF should have...)
--if you pull the axle, you gotta pull the CVs. If you pull the CVs, you need to swap in the entire wheel hub assembly from a 2wd Pathfinder...on both sides...and that job will suck. I suppose you could disassemble the CV and leave the outer shaft in place...but that would be funky. An option nonetheless.
Bottom line is that the drivetrain, suspension, and steering components are easily available and fixed. I can't imagine there not being a junkyard near you that has everything you'd need.
Sorry the long post, and especially sorry you've been put into this situation.