I've been playing around with this a bit more, and have added some preliminary code to provide read/write support for the PhotoStation trailer. It still needs some testing, but I have uploaded a 6.51 pre-release with these changes for you to play with if you want.
I have decoded a bit more information since my last post,
but I was wrong about the crop position being in inches (I
haven't figured out what units these coordinates are in yet).
You can use the -U option to see unknown tags in the crop
information, and the -v3 option to dump the FotoStation
trailer records in hex.
I'll let you know if I discover anything else.