CSS defines a pretty robust syntax for building responsive layouts with @media queries.
It would be exceedingly cool to be able to use them in this context to target device families and orientations. Perhaps something could be implemented with Auto-Layout Constraints to this effect.
Anyway, just wanted to put this out there as a feature request. Really psyched about the direction and momentum of this project. Well done, @tombenner!
(By the way, this was totally @dominic's idea originally. That guy is way smart.)