With the help of XPostFacto, my little Powerbook 2400c (400mhz Interware G3 card running OX, with 112Meg RAM, and hacked PCMCIA card drivers) is running OS X.

Shown here as a visual comparison with the 12" G4 Powerbook (1st generation).

**UPDATE** I later upgraded the 2400c to Apple OS tiger 10.4.1, but video issues and no PCMCIA hack resulted it a reversion to 10.2.8.