For desk work that is not typing, look into a gaming keyboard and mouse. My drafting co-workers have bound short macros to the extra keyboard keys for frequently used commands, I am weighing the benefits to use the same approach for frequently used equations during design calculations.
I had good results with CopyPaste, a program which creates multiple clipboards you can store things in on a semipermanent basis. ctrl-shift-v-2 could be the command to paste the second stored clipboard, for instance (depending on your settings - it was very configurable). That only works for things that allow the use of the edit menu - not palette hotkey selections - but it could be a help.
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.