Theoretical design connecting Raspberry Pi Zero (for compute/Display power) to Arduino (nano footprint) (for real-time bit banging/etc.) "Hairclip" (smaller than a "hat", right?)
Also an indication of the relative size of the RPi-zero vs nano...
(I'm just playing around. I'll be waiting till the RPi0's drop back down to $5 before I even consider getting one, and I'm not really sure whether this combination makes any sense, or would be economically viable for anyone to manufacture...)
Kind of cute in a way.
I am interested. I like the Nano form factor. Packing more processor into less space is always something I am after.
I make aboard that plugs into either a nano, Arduino or Mega(Due) and supports quite a few configurations of breakout boards as plugins.
Form factor is very usable.
This would be a useful start, but it might make sense to put jumpers on the board to make connecting the Pi to the Arduino's via SPI or I2c so that they(the arduinos) could act as an I/O sub system to the raspberry.....locally. maybe an RS485 chip hat for the zero instead for ModBus Arduino slaves?? I think so.
LIKE THIS.....
It was a rather academic exercise if RPi Zeros are only going to be manufactured "occasionally" as publicity stunts 
I can run this board at 3.3v with a Due or arduino ZERO.....a ZERO to ZERO bridge in this case a bridge to nowhere....HA!
I guess I could put the Pi master header here on the top back to back with the due header....I would put permanent straps in for 3.3v operation instead of the voltage operation selector on the lower right of the board...as the layout can also be used for the 5v family.... there are three HX711 load cell interfaces, wireless NRF24L01 could be kept, two rs485 ports, the other SPI ports could become slaves to the PI. the I2C bus is pin matched to the Adafruit ADS1115 BOBs, and I have a daughter i2c for the MCP4728 quad DAC.
