This board connects directly to the back of the 7" GLCD using a 2x20 .1" header. Demo code is included that allows the board to be tested as an I2C device or as a 1-wire slave. It uses the Teensy3.1 mini-board, and an updated eagle library that breaks out all available pins.
Sample code, Gerber files and the eagle sch and brd files are available at my github site
The Teensy3.1 pinout is based on my own design shown here.