Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
kntgsp said:
I'd be worried about the lifespan of the powerbook. It wasn't designed to be running with the monitor closed. They are wired so that the monitor cannot be on when the laptop is closed.

Has anybody had problems with this, or heard of anyone?

Apple says yes.

http://docs.info.apple.com/article.html?artnum=86286

You can use your PowerBook G4 (12-inch) and PowerBook G4 (12-inch DVI) computer with the display closed when the computer is connected to an external monitor, keyboard, and mouse and the power adapter is plugged into the computer and an outlet.​

iBooks, however, are a no-no.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.