Unfortunately, it's getting harder and harder to find PowerBook G3s for sale - especially working examples. If you can find one however, I'd recommend the Pismo which features two FireWire ports and either 400 or 500 MHz processors.
3x Apple Mac Powerbook G3 rare Black spares repair
Time Remaining: 23d 12h 14m
Buy It Now for only: £90.00
Apple Macintosh PowerBook G3 Series laptop Computer 4GB
Time Remaining: 19d 8h 25m
Buy It Now for only: £12.99