Dream Motorhome!

I have a dream! (Apologies to MLK). I want to own a double decker bus and convert it into our dream motorhome. Something Classic, but secure of course. Downstairs would be bedroom and bathroom, fixed bed, good sized shower, onboard water and some sort of sophisticated toileting system. Upstairs would be a galley kitchen, not too large, but good storage and room for a full oven and fridge freezer. Then, the piece de resistance, a large lounge area opening onto a sun terrace sort of bit at the front for viewing and chilling. It would have a roll back roof and sides for cooler days of course. Got to get reasonable mileage as well!