PIPduino looks like an Uno with optiboot bootloader and ATmega328P running at 16MHz with the same kind of crystal resonator on a Pro Mini.
What sets it apart are the color-coded signal, VCC and GND rails and dedicated peripheral ports (I2C, SPI/ISP, Serial) that I started using on RoverMux and RoverBaseboard.
The current version R0.2 uses an NCP5500 regulator in DPAK package, rated to 500mA. It features reverse protection and thermal overload protection; 230mV dropout voltage; and 16V maximum input. Run it off of ~3.53V or ~5.23V. I did some research on thermal design and implemented improvements. Testing shows the regulator will put out 500mA at a stable (albeit really high) temperature.
More about power. Flexibility is key with embedding these boards. You can power the board on any of the VCC/GND rails. There's a set of power rails for input or output power. And the FTDI powers the board, too, through a diode so you can do final programming/prototyping on the bench.
R0.2 features some fixes to the FTDI and to the bypass cap for the AREF pin. So far the ADCs are seeing much less noise than in R0.1.
So, I'm pretty close to releasing this thing on the unsuspecting public. Just a bit more testing to see how it works and I think we're good to go.