[znpy]

I'd probably work on a mobile phone, based on some sort of SBC like rPI Zero or the Chip Computer.

But I'd work more on the hardware than on the software: I want a physical keyboard like the one the Nokia N900 has and I want a physical kill-switch for the GSM/UMTS/whatever radio.

As for OS an apps, i always thought that some GNU/Linux distro with some small-device-optimized wm and good selinux per-app policies could work very very well.