Yeah I've got one more. BTW I also carry a spare on my own bike, if you take it out of the housing it's really a small and light piece!
There is also discussion in another thread about an aftermarket replacement. I don't think there is any experience with it yet, but if it turns out to be good quality that lasts it will be a much cheaper alternative to the BMW part.
One rider who was stuck in Russia (?) used a generic Bosch pump and that didn't really work as he is on his second or third now, not sure what the reason is.