Help,we need a caravan for a 6ft 8ins dad!

We are a family of 4 and we need a caravan with a queen bed and internal height measurement to fit a 2m tall dad. We have been looking for about two months and besides the Jayco Expanda and a Coromal Poptop, both with not enough storage for us , we haven't found much. We want to spent about 8 months travelling around Oz and as we are first time caravanners we've been looking at second hand vans. The kids will be doing distance education so we need a bit of space. We've thought a double axle, 17ft+, with a/c in the roof, poptop?(if that is possible with a/c in the roof), we are still undecide about the shower and loo, queen bed plus bunks or a double bed. I've spoken to every around Oz traveller I can find and only one has said they know someone who had a van especially made for a tall person but when we rang they'd sold it already. So I thought I'd ask, "does anyone have or know of someone who does have a van that was built for a tall person that they want to sell?" I know we could get one made especially, but as novices I think this would be a bad idea. I'd appreciate any feedback. We plan to leave late March/early April so time is running out.
Thanks for your help
Maree