Good to hear that you're thinking of re-building.....

....
You may of started to think about how much its going to cost to rebuild.
One of the parts you need to find out the price for is the Aluminium sides/roof.
A guy from one of those Motorhome magazines had to replace one side of his camper as it had started to de-laminate. Just the one sheet of Aluminium alone cost him £750. As it had to come in one extra large section that ran the whole length and height of the Motorhome body.
Yours looks like the sides and roof are in sections so its going to be a lot cheaper.
But I really do think what he paid was expensive anyway. as a rule i work at £20 - £25 square meter for 1mm thick..
This is a site that will supply aluminium sheet in sizes up to 6meters x 2 meters. They will also cut and process for you. Shop around tho....
http://www.metalweb.co.uk/default.aspx?id=12