Manucc1, a member of Spanish community Elotrolado (linked above), believes there may be a possible PS3 exploit in the PS3 Controller... although SIXAXIS or DS3 is not specified, and it could work in a similar manner to the Pandora Batteries in the PSP.
This claim is based primarily on speculation that in the PS3 controller there is a chip that is the same as on PSP, and it is alleged to control Firmware in some fashion.
Info on the chip is available
HERE, and a list of IC chips in PS3 is available
HERE.
This EEPROM chip may allow Firmware to be installed (when you install Firmware on PS3, you always have to use the controller... before 2.1, you had to plug the controller in via USB).
For those who don't speak Spanish, they are currently looking into the contents of the chip and seeing whether this will lead to anything more.. but have long way to go yet.