This sounds like a cool tool but I can’t try it myself as it is Windows only.

       Deploying a customized version of the Firefox web browser can be quite the daunting task. It does not really matter if you are a home user who wants to copy Firefox to another PC, or a system administrator who has to deploy Firefox on hundreds of PCs. Home users can use Firefox backup programs like Febe or Mozbackup for instance to copy their extensions and settings to the new computer.
Firefox Addon Maker offers to create custom Firefox installers that will not only install the selected web browser version, but also add-ons, plugins, bookmarks, passwords and other custom preferences…

…The program and the created installer are compatible with all recent 32-bit and 64-bit editions of the Windows operating system. “

Source: ghacks.net
 Create A Custom Firefox Installer with Add-ons, Bookmarks And Preferences