The 5.7 Release supports full export of bitmaps now.
We are presently making steady headway on the GEO data chunks. These chunks appear to be in two parts, and we are pretty sure the second chunk indexes the first. While the first chunk is not yet deciphered, we are confident that it contains geometry data.
With the recent addition of a new developer to the project (namely me), the PiggViewer project has gone opensource. Interested developers that have a knack for reverse engineering binary file formats are welcome.