I'm mainly a trackball user, since Joe rightly convinced me it was the key to solving ergonomic problems that had resulted in a bad case of "frozen shoulder". I do still have mice on some machines, but don't use them much. The exception is my laptop(s), where I have been unable to find a suitable trackball for mobile use that I can rationalize paying for.
ExtremeTech has a review on a "pen" mouse. It looks very, very attractive, though I will have to wait for later models which will better the current model's 400 dpi resolution. When they come out I'll pawn something if I have to to get one. (I wonder how much they will give me for a cat that loves to type? I could solve two problems at once that way.)
Anyway; the idea of a "pen" mouse is one I like and I cannot wait for them to be just a bit more capable.