A few other ideas, within older OS X accessibility, involve settings and the use of
'sticky keys' and the mouse; ie: you can click on single keys in Keyboard viewer.
Selecting them, however, requires single movements for each; unlike a quality
voice control method for the computer that would allow customizing the full OS.
Use on-screen keyboard in OS X?
http://www.bbc.co.uk/accessibility/guides/keyboard_easier/onscreen/mac/os_x/inde x.shtml
Use keyboard with one hand in OS X?
http://www.bbc.co.uk/accessibility/guides/keyboard_easier/one_handed/mac/os_x/in dex.shtml
Find a keyboard or mouse hard to use?
http://www.bbc.co.uk/accessibility/guides/movement_index.shtml
You could turn on and customize keys in the keyboard preference panel, and these may help
make use of settings in the 'universal access' system preference panel, in older OS X versions.
There may be some suppliers of peripheral devices such as you'd need, however
to locate them may be almost impossible unless you can narrow the search to those
companies or businesses which cater to persons with accessibility issues.
Inclusive Technologies?
http://www.inclusive.co.uk/useful/index.shtml
A USB ten-key, not part of keyboard, if the keyfaces were changed and could be 'function shifted'
in software or its firmware, to work as a smaller keyboard for letters and numbers, would be OK.
Someone must be making these, if not for accessibility users, for those with space considerations.
Not a mainstream necessity; and by far, would be less trouble to accurately control a computer without
having to stand by a giant display and rub ones arms, hands, & change postures, just to make it work...!
And some of the problem is when software makers choose to capitalize on one method of input to use
a product; such as touch-based devices. And those which use giant displays, yet waste a lot of space.
{If you choose to attempt to upgrade an OS X, be sure to look into all angles first... you may find the
idea may be compelling or helpful in one aspect; but may cause some difficulty in other aspects. To
get a later different computer or device that can use a newer OS X or iOS, and keep your old one
as it is, at least keeps what you have now intact, for awhile longer. Even if not convenient to use...
You may need to discuss the situation with an expert at an Apple store, and hope they listen well.}
Well, if I find anything else, I may attempt to post back here. My life away from an online-device-world
is rather limiting my actual living; I try to help others, & haven't anyone to help me accomplish my tasks.
Oh well...
Good luck in this matter! 🙂