Autoreplace:
/etc/palm/autoreplace
----- subfolders for various languages

Files related to built in apps:
/usr/palm/applications

Files related to 3rd party apps:
/var/usr/palm/applications

PNG files for emoticons:
/usr/palm/emoticons

PNG files for things like the lock screen padlock:
/usr/palm/sysmgr/images
-----may be useful for building themes

Fonts:
/usr/share/fonts

If anyone has any other path info to share feel free to reply.