Here is the source code for the board and schematic (in EAGLE CAD) and the firmware for the ATMEGA328P running the Arduino bootloader. We will be uploading the KICAD schematic and board file soon.
Current version: Zip file of complete source for Tracksoar: Tracksoar Source
Everything except the ltc3426 boost converter, GPS, Transmitter, and battery terminal can be found in this cart.
LTC3426 can be found here.
Battery terminal can be found here.
The transmitter and GPS can be found here.
Previous version: Zip file of Tracksoar V1.1 and shields source: Tracksoar V1.1 Source
Previous Tracksoar cart: http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=39350b4846