For those who might be interested, I've drawn up a prototype, as per attached. As mentioned, this will fit into a MSA DS40 drop-down fridge slide with an extended width.
In the front bottom left cavity will be a stove. The right cavity will be a Coleman Hot Water on Demand. The cavity at the back will fit 2 x 4.5kg LPG bottles. The other cavities are for food and utensil storage. Constructive criticism welcome
The left bottom door will hinge down, allowing the stove to be pulled out for use, and access to the middle drawer. The top left door will probably hinge up to allow the drawer to pull out. This drawer will be very high, but unfortunately there's not much I can do about that. Alternatively, there will be no door, and the drawer face will sit flush with the bottom left door.
The right door will also hinge down, and allow room for the hot water system to sit, and provide a bench for extra food preparation.
The back door will hinge upwards to allow access to the gas bottles.
I've already fitted the fridge slide, and it pulls out and swings down perfectly, just allowing the canopy door to close, and the drop down action to clear the canopy. Once dropped down, I have access to the back of the kitchen.
The only thing I'm yet to factor in is the height of the slide tray walls - this might mean having to raise the height of the bottom door hinges etc to allow opening. Not too concerned about that, as it should be easy enough to factor in.
I'm thinking about a Lido stove http://downundercamping.com.au/product.php?productid=16967&cat=0&page=1. Anyone used these, or think of a better option? I'm willing to change the cavity size to suit, if necessary.