"But the nature and structure of the propulsion system determines the shape" you say? Of course. However we're not at that point yet. We're trying to popularize the concept among rich kids. The popularity of the post with pictures of futuristic luxury Zeppelins shows that a sort of cultural momentum is building for flying living quarters. The Atlantic had an article about hipsters having a strange cabin fetish. Well, we're taking the cabin into the sky and ripping off the impractical geeky steampunk airship nonsense off it (although we must admit that art deco still has its charm, see below).
We do have some guiding principles though beyond cynical marketing.
1) The house should be a lot faster than most current blimps and thus utilize sufficient angularity borrowed from the ongoing efforts of Boeing and Northrop Grumman to win lucrative unmanned aerial vehicle contracts. Yes, there's dozens of countries developing drones but we should focus on which players have the most money, technology, resources, and talent to work with. The futile struggle to keep China out of west Pacific is serious business and so far our flying house shape borrows the triangle heavily.
Rome wasn't built in a day as can be seen but we want the flying house to utilize every side like a real house would and/or hopefully be able to spin on its vertical axis (if not move sideways and backwards when needed).
2) The shape should be thick enough to accommodate up to 250 square meters of space (average US house in 2009 up from 130 sq meters in 1970) without fully resorting to oval/cylinder aerodynamics of a futuristic blimp.
3) Once again, it will not be powered by a sack of gas and neither will it be too fast. So no insane scramjet shapes (see below).
There's a dozen other more technical principles that are not relevant to the shape as much. In essence, we'll take the best of the high tech DARPA and amateur airship concept art, the best of the drones, and integrate it onto a sturdy floating platform spinal chord that extends its ribcage support beams throughout the whole house. The final product will be designed to be visually and psychologically marketable to the tastes of a certain elite demographic. Cultural, subcultural, and technological trends point to flying houses and we'll see you next time about this.