Actually, what I had in mind wouldn't involve changing any coordinates, just displaying the same axis multiple times. For example, right now I can use the "The x-axis crosses at y=" field to move the x axis from y=0 to y=2. This doesn't affect any of the functions though. What I am suggesting is simply to allow both those choices to display at the same time. They are the same axis, just displayed in multiple places, so the functions and point series shouldn't need to be associated with any of them.
Then again...Ivan, I think your idea is actually useful also, maybe even more useful. Sometimes I do want to make a graph to display more than one quantity at once, and then you WOULD need differently scaled axes. For example, a graph of both temperature and pressure over time would require two differently scaled and labeled axes displayed simultaneously.
These are both actually possible to do at the moment, but it involves a little "cheating" by copying an image and pasting it into a text box (see the attached file).