Putting a MacBook's easily removable battery on a MacBook Pro

I supposed this is more of a mod than a fix but I believe this would be the right crowd to ask. What I'm wondering about is weather or not is would be possible to take the battery and back cover from a unibody macbook (that has the latch to easily remove the battery) and putting it on a macbook pro for the convenience of switching out the battery on long trips or situations where there is nowhere to charge like long flights for example. thanks for any help or information you may or may not have.

-brandon