I'm currently working on a port of FreeRTOS.org. I'll SVN my stuff when It's done, but it might be a limited solution for other people....
Pretty much the useful stuff for every one else will be a command handler from taking commands from i2c and the kernel port itself. the command handler will take a command character and a some data associated with that command (in my design it will take up to 36 bytes), then parse the command and carry out the action. This is going to run on interrupts from i2c so as to not use up valuable serial resources of the gumstix.
what's nice about this command parser running off of interups is that it will only run after it recieves an i2c command, and won't poll, so it won't be wasting timeslices of the os.
the non-general section i'm coding is several tasks related to taking measurements of a sensor on a sweeping servo and static perimeter sensors, outputing PCM signals for steering servo and applying PID (proportional integral derivative) to the ESC command (speed based not position based) as well as outputing a string to a serial LCD (from sparkfun...the 1337 white and black one....ooooo so nice!)