Originally Posted by Ephemerality
I've actually been working quite a bit over the past week on creating an x-ray builder that generates all of the loc and chapter information by unpacking the mobi file and running through the raw book content..
Edit #2: I hadn't thought about it, but since the Calibre version already has access to the book it could definitely be modified to add the locs. My version is a separate program done in C# so it's not nearly as convenient...
I actually thought about doing this as well, but had some problems with the mobi library I was using, as it seemed to skip some data and thus the locations were inaccurate.
It then also occurred to me that this might be much more sensible to do in Calibre, however once I started working on it, I got discouraged by the effort...
I'm looking forward to seeing your implementation in action!