This question regularly comes up on the forums.
We always get one side that says no problem and the other side that says it can't be done effectively.
Just try it out for yourself.
I'm not sure why adding another pump and controller will take up the space of other equipment. The biggest cost of space is the second hose reel you already have. You can use the same leisure battery for both pumps.
BTW we tried it, and it didn't work for us. This is the reason why we have a twin operator system. You will also notice that if you order a twin operator system from a supplier you get 2 pumps and 2 controllers.
The oldest Shurflo pump we have is over 14 years old and still working. That's not just my experience. They are a very good investment. Our 2 Varistream digital controllers are 12 years old; another good investment. We still have an old Varistream analogue controller working perfectly on son's van which is even older. He likes it as he can regulate the flow precisely which we can't do with our digital controllers.
As Ched says, the problem comes when switching off the flow to one pole. The pump will most likely start to cycle and I'm sure it will not be doing the pump or controller any good mechanically.