Our first rocket electronics project is a flight computer for @Phil's IRW rocket this year. @Matt and myself are working on it with him at the moment, but we welcome others if they want to join. The current board design is about 20mm*50mm and weighs less than 20 grams. It records altitude, attitude and GPS and also sends them to tracking stations via a radio link. More details can be found on the wiki page and Github page.
Rocket Onboard Computer (ROC)
I'm interested in helping out. For the CanSat 2014 competition I programmed an Arduino to collect telemetry and broadcast it to an XBee radio via serial. I imagine what you're doing is significantly more sophisticated and less hacked together though.
I also had to save the telemetry as a .csv file on an SD card so this is eerily similar.
Edit: This was the design guide with the requirements mission_guide_2014_release1.pdf