Recently I have been working on Packedobjects which included redesigning the API and replacing a lot of C code in Scheme. I will try and formalize the whole encoding process which I have called Integer Encoding Rules. I also began work on a manual which includes some examples. My aim is to support the tool on OpenWrt which also involves maintaining the GNU Guile build.
I built and tested the software on my Ben Nanonote. The ipk is available: http://zedstar.org/ipk/packedobjects_0.4_xburst.ipk
After improving the documentation I intend to use the tool in a networking course at work. I think it is important for students to gain some experience of designing and structuring binary network protocols. We will be getting a bunch of Nanonotes to compliment the Openmoko Freerunners we have. This will provide some nice hands on experience packing some data and communicating it across different kinds of hardware.
Long term, I am interested in designing some funky SlowFi protocols on copyleft hardware.