The Powerbook G4 12″ that I bought from Craigslist was sweet overall (1.5 Ghz, 1.5 GB RAM, 250 GB hard drive), but the keyboard looked a little ratty.
So I bought a new keyboard from a Hong Kong seller on eBay for $28.00 (including shipping) and installed it today according to the relevant faqintosh. Very shiny!
My only issue was getting the keyboard connector mated securely enough for all keys to work. And not knowing what a black stick is. 
Update: The Apple Genius Bar will sell you replacement keyboards for $40, installation included.
faqintosh.com: Remove keyboard on a PowerBook 12”
command-tab.com: Apple’s “Black Stick”
tuaw.com: Tracking the mysterious ‘black stick’
