We designed someshing similar, with the same connectors, and have some modules ready now (using them in our country, Argentina). We are not full open source yet, but will progressively release sources):
Sensors:
Beacons and buzzers:
Motors:
And this is our new DuinoBot brain, wich is based on an ATMega32U4, without FTDI or any other chip:
We will release a LUFA based core and bootloader, both open source soon.
Regards,
Julián