As far as I know the backup is encrypted.
> Are you not able to import these backups into the desktop client?
No, the desktop client is not standalone, and ONLY syncs with the a phone to get content. Moreover, if you don't use the client for a period (2-3 weeks in my experience?) it de-syncs that desktop client. Re-connecting that desktop to your phone will only sync messages starting as-of the connection, so there's no way to get the desktop app to pull your whole history. (This is another gripe I have about their sacrifice of actual usability for security that only helps a few very specific use-cases.)
You're probably rigth about hacking something together. Someone has created a library [0] allegedly for decoding the backup files. Friday night is D&D night though, so I haven't had the chance. :-)