Yes, you read that right a full 18 inches! Not some internet prescription scam for enlarging certain parts!
So, as you all know, the stock rear wiper sucks bad. Even the 14" Murano blade sucks.
This is my first car with a rear wiper and I was pretty pissed that the wiper was that bad. So, I set about a long arduous journey to find a cure for the bad wiper blues. After destroying several other blades and an aftermarket Jeep YJ wiper arm (17 bucks into the toilet there), as I was staring at the broken carcass of the Jeep arm, it dawned on me, if I could add a peg to snap the wiper on then I could have any blade I want.
The Jeep YJ arm Fallout:
So, I added the peg . . . tested my 18" passenger blade on it and lo and behold it FITS, the tip of the blade goes right up to the top of the glass with no run over (only the plastic tip of the blade went over). So here it is, the glorious 18" Rear Wiper Blade Mod:
Get a 1.5 inch Machine screw (mine was #8-32), 1 nut to match (again #8-32 here), 2 washers one or 2 sizes bigger (i used 2 #10 washers), 1 washer the same size as the screw (i used a #8), a cap nut to match the screw (once again #8-32), and some blue threadlocker. (you might want to spray paint the parts black to blend in)
Remove the wiper arm(only needed if you want to tighten the spring, see later), the plastic cover over the attachment pops right off, it's a 10mm nut holding the arm to the motor shaft.
So here's how it goes together: Screw/#10 washer placed into the groove that clipped the OEM blade, then another #10 washer and the nut. tighten down good (don't want it to slip out) and threadlock that nut.

Slide new wiper blade over the screw and clip into place (yes, you must have a wiper that can work with the clip models) add #8 washer to the free side of the screw on the top side of the new blade, finally, add the cap nut and threadlock it (don't tighten too much, you want a little rotational movement on the blade so it can sit flush on the window).

To finish, retighten the OEM 10 mm nut to the shaft and replace the cap.

Now stand back and revel in the glory of a fully functional 18" Rear Wiper Blade.
BTW- I bought a Bosch Evolution Beam blade, it has a pretty good bend to it and was too much for the factory spring, so I took a ziptie and zipped up the OEM spring on the wiper arm. this pulled the blade tighter to the glass.
pics on the car, i just figured out how to make the flash work

it looks like it comes off the glass, but the blade only comes off less than 1cm and no contact with paint or other parts of the hatch
Enjoy!