The two ideas combined are exactly what I plan to do when I start my build:
1. Get the Long Range (or Long Ranger) fuel tank that mounts next to the drive shaft (on the other side from the stock tank)
2. Cut out the cubby and weld a flat sheet over it.
3. Move the muffler / get a tiny one.
4. Mount a solid water tank underneath where the cubby/muffler was.
I'm hoping to fit 10 or 15 gal under there, I need to crawl all over an 07-11 JKU to get measurements and figure out if I'll need a different rear track bar and how big it can be before changing the departure angle.
Obviously it will need a skip/protection back there.
-Dan
They sell that for the 2012+ ? According to their site it won't fit a 2012. "Model Fitment: Fits All Petrol Models 4 Door Wagon (Will Not Fit 2012 Models) " I wonder if that's just the evap or something else?