The Ultimate Kombi bay-window camper.. How would you do it?

No you don't need to spend money on souped up aftermarket brakes. You are building a comfortable, versatile lifestyle vehicle for cruising, not a race car. Factory campers used stock brakes all their lives and they sold 12,000 of them. Reconditioned, top-condition stock brakes (ie new master and wheel cylinders, new pads etc) will be more than adequate, so just make sure everything is fresh and 100%.

Stock campers had flyscreened openings in the pop-up roof material, with zip-over covers in roof material. I am not sure that 'clear' would be the best way to go, as you want the option of complete privacy. The stock roof skylight (with VW symbol in it, of course) had a swing-down aluminium frame flyscreen too.

A flyscreen curtain over the rear hatch opening would be a great idea, as you could camp with the hatch open and keep the mossies out. You could make it out of normal plastic flyscreen material, and use a flexible magnetic strip sewn into the top of the curtain to simply stick it to the Kombi's opening. Don't forget to make another larger one for the side sliding door, again with a flexible magnetic strip along the top and sides.

I didn't worry about a drivers' overhead console - I am 192cm tall and my head only just clears the stock roof lining. The dash is more than adequate for maps, or you could also made a driver's door pocket, like a 40-bhp Beetle.

Yeah the brakes will be re-coed to begin with. I intend to develop a Kombi brake upgrade and my own Kombi will be the first test unit.
I hate maps and stuff reflecting in the windscreen from the top of the dash, so I'll install an overhead console to store maps and clutter... Good idea on the door pockets, Phil, mine needs new door cards so I'll probably incorporate some