Thunderbird 7.0.1-r1 became stable last week and is now emerged on my development system. That means I can start testing the compatibility of ThunderSync 2 in Thunderbird 7.
In addition, I am working on the IMAP synchronisation feature. Right now I am designing a preferences dialog to choose a folder or a message of an IMAP mail account. ThunderSync will then look for attached files compatible with the user-specified format — for the foreseeable future this will be the vCard format.