I had come to the same conclusion about the custom setting..
However to see if it really works one needs to know what camera settings are customisable, and what instead can only be set manually. The Mirror lock-up should be easy to customise, but I am wondering about the timer button, whether this can also be set in the custom function..
However a much simpler system would have been to have given the Print button (new) on the camera the function of mirror lockup with self timer 2 seconds.. So easy.. Or just add to the shooting mode another choice, 2 second + MLU.. Must camera manufactures be so difficult when giving us solutions?
This just re-inforces the view that camera engineers must do gardening as a hobby instead of taking pictures with the machines they design... :-)