Well, an update, though not one I'm happy about. I think I may have found the problem. I found a section of the logic board towards the very front, near the front latch, that looks to be burnt/shorted out. Included in this section is a chip that appears to be marked "4172 EUA". I'm not sure of the role this little guy plays in the operation of the iBook, but it certainly looks damaged.

Here is a photo I took to show the damage:



I'm not sure where to go from here. Is this a part that could be replaced by myself? I have very little soldering experience, but may be able to manage it. Even if replaced, this may not restore full function. Is it worth trying to repair, or should I just sell the 'book off as parts? Any input would be great.