Are PowerPC-based PowerBooks supported?
Many of them. See the NetBSD/macppc supported models list. The PowerBook 1400, 2300, and 5300 are not supported, because they do not have Open Firmware. Sometimes newly released laptop models have different built-in keyboard glue and it takes NetBSD a while to catch up. If you have a newly released model, try posting to port-macppc@NetBSD.org. Note that power management is not yet supported, so it is not possible to suspend and resume a PowerBook while running NetBSD. See also the section called “My PowerBook or iBook won’t power on, charge the battery, or recognize the charger”.