Originally Posted by
tiiger
Yeah, just use one of these type deals in your second cage. Should be able to fit a mini pump, no?

Even that is a bit much IMO. Again, nice, but not needed.
I'm able to fit everything that would typically go into a saddle bag into an ordinary bike bottle. Easy, cheap. Keep a second, exact replica of the "tool bottle" in your desk or locker at work in case you loose the primary on the way.