I found a BSD one too, unfortunately Darwin/Mac OS X has different USB stuff, so it doesn't work. It's at the bottom of the FTDI page on EEPROM utils. Anyone want to try a port to GNU/Linux and/or Mac OS X?
http://www.ftdichip.com/Resources/Utilities.htm
http://www.bwct.de/ftdi-eeprom-1.0.tar.gz
A port to libusb would make it work on both GNU/Linux and Mac OS X (and perhaps even Windows).
I just had another related thought: it would be awesome if you could access the FTDI EEPROM from the Arduino code. Then you could set the "event character" in your code. I don't know whether it's feasible though.