This really isn't needed if you use Package Control. If you have package control, all you need is to back up your User folder.
Package Control creates a file called Package Control.sublime-settings in your User folder which keeps a list of all installed packages. So, if you just backup your User folder, you can literally drop it in a new installation, install Package Control, and Package Control will look at Package Control.sublime-settings and automatically install all of your Packages.
Since custom settings for packages are always stored in User, your settings are also already consolidated.
If you use certain packages that are not currently in Package control, you can the repository to your Package Control.sublime-settings file, install the package via Package Control, and now that package will be tracked and will be installed automatically as well.
If you have written your own custom script plugins that you don't have a repository for, you could just drop them in your User folder to keep track of them.