I've managed to read and start to decode the messages on the multistrada's canbus. Early days so far as there's a lot I'm still trying to get my head round, but can already read things like; rear wheel speed, gear position, engine temperature, indicators, brake light, battery voltage, DTC setting, engine mode and rear spring preload. I'm in the process of trying to work out throttle input and resultant throttle position, engine revs and suspension settings (this last one is a bit frustrating because of all the variables).
Reading and logging the canbus info is surprisingly cheap and easy. All you need is a small microprocessor. I'm using an Arduino UNO, about £25, and something to read the CAN messages, a Sparkfun Canbus shield, about £35, a microSD card and a home made lead to connect to the diagnostic plug under the rider's seat. Oh, and some code to read the messages and write the to the SD card.
It should be really easy to adapt the code I have to make some sort of data logger or supplementary LCD display. In theory it would be possible to get very ambitious and replace the existing DES module with a homemade version and save £100s in the event of a failure, or even make a speed sensitive one (both these are obviously significantly more complicated and time consuming).