Still hoping
Waiting
Have you tried booting into OFW and exploring the device tree etc. to see what's available? I don't have a 12" I can test with. There seem to be a good amount of PowerBooks (particularly the smaller form factors and Ti models) that don't have a `fans` device you can interact with. For example the PowerBook Pismo uses a `thermal-info` property instead which only really works with an On (full speed) and off functionality, the Ti is similar. https://mac-classic.com/articles/controling-the-powerbook-g3-pismo-fan/
A good start would be to explore the device tree to look for `fans` or the `via-pmu`devices and methods.