I am having a lot of elbow pain from my cad work.

I am using a track ball and have been since the turn of the century. I have tried them all, Pens and pads, balls and mice. Even the high end space balls.

I have been designing one and may be doing a kickstarter introduction. BUT..................

I don't think this is a million dollar idea but it has helped with the pain in my arm and it might help others.

I have a design concept, sone sketches and hand built (functional) models but If I am going to take the next step It would be great to hear what the community has to say.

My concept is simple.....really simple.

But from what I have read here are some of the common concerns.

The ball is too small.  Would anyone like a bigger ball. like tennis ball size?

Its not easy to switch from left to right.

no scroll wheel for rotating.

not ergonomic enough.

It's not easy to do a left button hold and roll the mouse.

These are pretty general. Are there any specifics?