The product on android that I used before was locale which offers a wide range of customization options - http://www.twofortyfouram.com/product.html

I think one of those was phone orientation, I guess the idea I had in mind was to turn it over and automatically switch to silent profile or something along those lines.

The default rule worked really well in locale as it always set the phone back to a default state when no rule was in effect.

Regarding overlapping rules, would you enforce the logic that only a single rule/profile could be in effect at any given point in time? Does this really need to be enforced, ignoring this would potentially remove some of the complexity...

By the way, always great to see a developer actively engage the community.