This guy has a great write up on how to put on and take off a high roof on a van, very similar to that of a westy if I understand correctly, so this may give you some ideas and thoughts as to how to put this thing on there!
It will be pretty cool to see.
OH and on the thought of opening it up over the rear end, that requires a LOT more structural engineering than you imagine. There is a reason That XV-JP sells for 100K and the flippak JK sells for about 4K. The flip over the front allows you to put polls down on the hook of the truck, without that you would have to find a way to support free hanging a bed off the end of your truck. Just saying...
"Do you know what a soldier is, young man? He's the chap who makes it possible for civilized folk to despise war." -Allan Massie