Well, despite my belief that I had found a fix to my disappearing battery problem, this morning when I woke the powerbook from sleep, the “x of doom” was back.
I have this weird fix where I can pop out the battery and reseat it while I’m plugged in and get things to “hold” long enough for me to commute between work and home without having to shutdown and reboot. But I guess I’d better pursue a replacement battery too.