Kaymar makes a rear bumper for the Navara with the spindles and everything. You'd have to make the swing outs. Problem is there are frame differences between ROTW Navaras and US spec Frontiers, so I'm sure it'd have to be modified. At that point, I'd just as soon have one custom built.
And stay away from TAG. Formerly known as KMA. They have shoddy workmanship and terrible wait times.
Here's what I'd do. Find a design you like, then look around for someone who is willing to make a bumper for you (of sufficient quality). You can do anything you want with aesthetics. Make it whatever shape or design you want. With a swing out bumper, the most important things to consider are the hinges you're using and the latches.
Hinges:
If they suggest using trailer spindles, move on. I think hinge setups like these are the best options:
http://www.comp4x4.com/Tire-Carrier-Hinge-Kit-with-Double-Shear-Bracket-STANDARD.html If you're concerned about this one, use the HD.
http://www.comp4x4.com/Tire-Carrier-Hinge-Kit-Dual-Shear-Face-Mount.html This is what I'm using for my swing outs.
I like dual shear. Minimizes the odds that a hinge will snap off. Much more stable and durable design. Look at the the swing out on a newer Hummer. It's dual shear, and they are solid. Shrockworks always use a dual shear design of some sort.
Latches:
http://www.amazon.com/DE-STA-CO-341-R-Action-Threaded-U-Bolt/dp/B0006NC6AI/ref=sr_1_1?ie=UTF8&qid=1390684680&sr=8-1&keywords=de+sta+co+341-r I like these. That's what I'm going with.
There are numerous options here. I like to have at least one locking mechanism. Maybe two. A sure fire way is a bolt with a T handle. You can also get latches like that with holes for a pin or a lock, you can get spring latches, etc, etc. The most important thing is to completely immobilize the swing arms. That will minimize the wear at the hinges. Also, you should mount some sort of rubber isolator on the arms that will ride between the arm and the bumper. This will help isolate vibrations and provide tension to keep the whole thing solid and secure. If you use the style latch I'm going for, the latch should be mounted at some angle, not just straight, so that it actually sucks the swing arm towards the bumper when you latch it. Again, this keeps the arm as secure as possible.