I'm actually using two keyboards for one Mac. One keyboard is on each arm rest, so I can optimally relax my arms. It's like the concept of a split keyboard, except it's wide enough for my chair and I don't have to type properly.
I wrote this executable which will make modifier keys from multiple keyboards affect each other on the same machine.
I just registered in order to say thank you. I have a foot pedal thingee that I wanted to apply a modifier key to but couldn't get it to work. Thanks to you it now works beautifully.
Dual Keyboards Solution
http://dotdotcomorg.net/Mac/DualKeyboards.zip
I wrote this executable which will make modifier keys from multiple keyboards affect each other on the same machine.
Only tested in 10.5.5, but I don't see why it wouldn't work on other systems.
Now I have to get out of the habit I grew of using the same hand for modifiers.
Special thanks to: OS X Book.com and The Mac OS X Reference Library
EDIT: You must have assistive devices enabled in the Universal Access preference.
If you set it as a Login Item in your System Preferences, it should start automatically. Could you give me some details on what happens when it stops working?