Hi Duppie,

Is there a reason that you would want a side mount gimbal? People do all sorts of creative things.

I almost never use my monopod, but I am just trying to think of using a gimbal on a monopod. I am not sure I would do that. Gimbals are great on a more sturdy tripod. My gimbal is a side-mount. But the primary advantages of a gimbal, at least to me, are more about when you are not actually shooting, you can take a step back, let go of your camera, rest and your camera stays in relatively the same place without falling over. With a monopod, its going to fall over. As for the smooth action you get in use, the monopod base rotates smoothly in the z-direction, so all you really need for smooth movement with a monopod while in use is a good tilt-mount for the x-y axis.

Now, if you monopod is going to be fixed somehow and cannot rotate, or fall over, then I can see the benefit of a gimbal. I use a sidemount RRS gimbel:
Gimbal Heads | Really Right Stuff

Mine is a PG-1 that is sidemount. I know others have move to the FG-1 for the even smoother action that the fluid head provides.

Thanks,
Brant