At the moment, we tend to build up the storage room, technical room, and study. Then a small wooden staircase going up would be sufficient, since you don't have to go upstairs all the time. Better to build like that than single-story with a cold roof, because otherwise a lot of ground area would be lost again. We want the garden to be as large as possible. So far, we use all of that as a garden.
No, a standard design cannot/will not become an option. We have too "special" ideas for that. And it would also have to fit into the development plan. That's rather unrealistic. Better to build with a local provider who is not super expensive, but implements our ideas and delivers a high energy standard.