ZeroPhone is a project I started shortly after I discovered ZeroNet. It's a continuation of a long line of "phone" projects I've had that have less to do with telephones per-se and more to do with personal, portable computing devices (which we currently happen to refer to as phones).
Additionally, I had a really hard time convincing anyone that building such a device with such an architecture was the way to go, and I had a hard time getting anyone else interested in working on it.
So when I came across ZeroNet, it was a validation of the concept and I immediately started noodling on how I could put it to work to realize something like the BitPhone project, hence ZeroPhone was born.
So far this has amounted to finding suitable embeddable hardware that is capable of running ZeroNet. Since I'm still learning about the system I wasn't sure how hefty the hardware requirements would be, so I started at the bottom of the parts bin, which happened to be Next Thing Co's "CHIP". I was pleasantly surprised to find that, with the addition of a little USB flash storage, it ran the ZeroNet "server" software without much trouble.
Aside from the cost ($9USD), one of the best things about the CHIP is that it's Open Source Hardware, and the company goes to considerable effort to make it easy for designers to incorporate the CHIP in custom designs. This makes it a lot safer to design the CHIP into a product vs. something like a Raspberry Pi which has more complex licensing and incomplete documentation.
Of course this doesn't address any form of user interface, etc. but I have some unusual ideas for interacting with ZeroPhone than the typical touchscreen interface. That said, it would be fairly straightforward to connect a LCD touchscreen to the CHIP and turn it into a "normal" phone-like device that's "powered" by ZeroNet.
Today I designed a simple printable case for the hardware so I'm less likely to damage it while carrying it around. I'll be evolving the design as I add more components and interfaces to the system. Design files can be found on github.