In general: can you have two bluetooth keyboards controlling the same computer at the same time?
Specifically: can you have two of those Apple bluetooth keyboards controlling the same MacBook Pro running Snow Leopard at the same time?
Why on earth: the keyboard works great, but is way too narrow to be ergonomically reasonable for extended use. I could just replace it with one of those "ergonomic" keyboards, but even they (the ones I've come across) don't do the trick: most relaxed posture === hands are shoulder-width apart.
I say:A keyboard for every hand!

Picked up the other keyboard today -- it's working great!
The only problem is that the modifier keys (shift, ctrl, etc.) don't work across keyboards by default.
A bit of searching revealed a forum post where a helpful individual has created a tiny unix executable that takes care of this (on OS X).

I'm pretty happy with the setup, it's quite the improvement. I did come across this company however, while searching to fix the modifiers.
These things look like an even better solution (hadn't known they existed!), so I might try them at some point in the future.