CSA Engineering and Oberon Microsystems have announced the formation of the Mountaineer Platform, an open-source Gadgeteer compatible hardware platform for rapid prototyping.
The Mountaineer Platform's first products are a pair of Gadgeteer compatible mainboards. The Ethernet Mainboard has 8 Gadgeteer sockets plus onboard Ethernet and USB connectors.
The USB Mainboard has 9 Gadgeteer sockets plus an onboard USB connector; it is the smallest Gadgeteer-compatible mainboard to date.

Both Mountaineer boards are based on a 168 MHz STM32F407 microcontroller with 192 KB RAM and 1 MB on-chip Flash, running the NETMF port that was released by the Mountaineer Group in May 2012. They also have 8MB of external flash, a user programmable button and an RGB LED.
For more information on the Mountaineer Platform, see http://www.mountaineer.org/news/.
To purchase Mountaineer hardware, see http://www.mountaineer-boards.com/.