I’ve never tried a trackball keyboard, but I bet it suffers from the same accidental-cursor-movement problem that laptop trackpads do.
I’ve tried all of those trackballs except the “trackball mouse” and none of them are any good- at least, not for my hands.
No. Most of them are too small and light (the possible exception being the large Kensington). Many years ago, I used one of those Kensington trackballs that was the size of a cue ball, and loved it. I don’t want to operate the trackball with my fingers - I want to palm it. Nothing like a large trackball, provided it operates smoothly enough, for allowing you both rapid large scale movements and fine control. What would really be nice is one of those bowling ball sized deals that used to be on arcade video games, and still operated smooth as glass because it was mounted in massive gimbels. I hate to think of what they would cost and the desk footprint, though.
I gave up on it when optical mice started coming in. Mechanical tracking simply has its drawbacks (yes, I know there are optical trackballs - most of them are little and lose the tactile advantage I’m after). The extra wheel and button controls for all these side functions are more difficult to incorporate into a trackball design, too.
Gotcha. You want something like the old “Missle Command” arcade game, which had a bowling ball in the center. Hmm, I wonder if you could buy one of those and adapt it for USB…
How about this?
Hmm. Interesting. A 3 inch ball with a USB interface. Of course, to use a gigantic trackball, it occurs to me that you might want to simply give up on having the mouse BUTTONS on the trackball device. When I’m operating the pointing device, my other hand is doing zilch. Rather than try to design the pointing device to have all these integrated buttons you keep pressing by accident, why not detach them onto a separate keypad operated with the other hand? Or dockable with the keyboard or integrated into it if your prefer. Many modern keyboards have custom button functions which duplicate the custom stuff on the mouse anyway. Your “pointing hand” could concentrate purely on pointing. Or if you really want to be perverse, use foot pedals.
I knew a guy who took apart an old Marble Madness cabinet and rigged one of the (bowling-ball-sized) balls with a PS/2 connector. He used it for drafting or somesuch.