The Arbor Linux Shield is a way to add Arduino Yún capabilities to most microcontroller boards.
Add the power of OpenWrt Linux, WiFi, Ethernet and USB to any Arduino or compatible board.
Run it with Arduino Yún software or as a standalone development board.
The shield can communicate with your Arduino through Serial, SPI, USB and has available GPIO pins for other options.
Check it out on Indiegogo. Arbor Linux Shield: An OpenWrt WiFi development board for Arduino & other MCUs. | Indiegogo
Thanks for looking.