even though apple hardware costs a lot, there is no way I'd go to a pelt system on a G3 233. Even if it is an exceptionally good core (like yours)
still remember though he is worried about fanless computing, and temps, so air cooling isn't really an option.
http://www.kdcomputers.com/exec/productProfile?id=433 that is a cheap air cooling solution, which even if you don't want to use it forever, it may give you an idea of what your cpu will do when well cooled