The Arduino would either send the program to the XMOS chip, or just flash an external flash chip connected to the XMOS chip, or even have the XMOS chip boot from a SD-Card. (possible?)
I'm dreaming, I'm pretty sure, but heck, maybe its possible?
The chip I'm talking about is this one:
http://www.sparkfun.com/commerce/produc ... s_id=10109
The idea is that the developer would have the actual XMOS Dev. Kit, once the firmware is good, he/she would just supply users with this. Then they plug the shield to an arduino and have the Arduino code send the firmware to the XMOS chip. Making it much cheaper for users to run those things with an Arduino.