While I'm usually the last person to ever suggest gadgets, This is something I think most of you will like.
I have already ordered one for my Daughter and Myself.
Too bad it isn't a Nikkor !
... UPDATE ...
I have received both the Nikon and Canon Cups and have to say they are both great. I used them on an outing with the Nikon filled with water and the smaller Canon filled with hot coffee.
The Nikon sample I have sealed well with no leaks. Very important if you plan to carry in the camera or lens bag as I do.(Outer pocket only) The canon type has a spill proof, but not totally sealed lid. Fine for in the car but not in the bag.
Neither of them are insulated enough to keep coffee hot for more than a couple of hours, but not a problem for me.
Overall I am very pleased. Great option over the standard water bottles I would normally carry.