I would refrain from commenting on the Neo as it would only set me off again.

But on the topic of Raspberry Pi and the like...

I never liked any DIY solutions based on Pi because they are all waaaay too clunky. The boards are not exactly designed for a pocket use.

BUT - isn't the design open-source? So in theory, one can design one's own board that would be much more convenient for a mobile phone form factor. With the advantage that it could run a completely unmodified OS.