I'm in the beginning phases of thinking about the design of the second PCB that will host the main microcontroller and wifi radio. The physical PCB itself will use the same 43x70mm form factor as the display controller, so they can be easily fitted together.

All I really know for certain at this stage, is that I'll want to stay in the ARM Cortex world, as that is what I am most familiar with. Maybe a Teensy would work well?

I will likely have the communication between the device & both the time-server and control apps be raw TCP. That way, I don't have to concern myself with parsing stringy HTTP headers and storing large HTML strings somewhere.

Finally, I'm toying with the idea about playing around with the MPR03 touch controller. I got a few samples from Freescale of this tiny (2x2mm!) 8-pin 3-channel touch sensor last week and have been looking for an application for them.