Grant - have you got the rear seat folded or upright in this pic?
Just to compare
The frustration I had with my rear box was the rear lip where the door shuts. Which sent me down the path of lift out boxes rather than sliding drawers. Lost too much space under that lip! And in reality, the ZJ/ZJ/WJ/KJ are not "deep" enough in the back to warrant sliders.
However, I have spent lots of time lying on my tummy in the Full Size trying to retreive stuff near the rear seat! It was deep!
Unit looks nice! More pics please (we have an XJ now as well - it's BLUE!)