Another user suggested using cloud services to store the filters so that you can share filter sets between computers. Instead, how about allowing us to store the filter (XML or however it is stored) on our mail server in a folder. (mail, notes, tasks, etc) We already have a shared server that all our devices are reading, so we dont really need a cloud account somewhere else to store the rules.
Create the folder
Configure Thunderbird to use that folder.
Create your rules (or import them from existing method. Maybe give us a choice to migrate existing rules?)
Go to other devices and point them at the same file on the mail server.
Now all devices are sharing a database, and when one device add/deletes a rule, all other devices have the change.