custom keyboard layouts

Different people have different typing styles and type different things. A C programmer will use many curly braces; a LISP programmer will use many parentheses; a UNIX user will use the vertical bar more often than most people; a writer will use mostly letters and whatever functions keys operate the word processor. Different people have different degrees of dexterity, and some people favor one hand over another.

So, have a program record keystroke statistics as you use your computer. (Make the program open source, so that nobody worries that it's logging the data and sending it off to someone.) After a while, it generates a recommended keyboard layout which is optimal for your particular typing needs. The utility program can then remap your keyboard to this new layout. It can optionally perform the mapping gradually, swapping a couple keys every day or so, to let you become gradually accustomed to the new system.

Furthermore, this utility records your custom layout in a central registry. Whenever you're using a different computer that is also running this utility, you press a special key (I propose "Scroll Lock") and then type in the name you have assigned your layout. The utility downloads the layout from the registry, and now it's all set up for you. When you're done, you can press Scroll Lock (or whatever) again and it reverts to its previous state.

The registry will come with common layouts like QWERTY and DVORAK pre-loaded as well, so any keyboard on this system can easily accomodate users accustomed to any particular traditional layout.