Reply To: Add additional customization

[Tom]

Here are some resources for you:

http://www.smashingmagazine.com/2013/03/05/the-wordpress-theme-customizer-a-developers-guide/
http://ottopress.com/2012/how-to-leverage-the-theme-customizer-in-your-own-themes/
http://code.tutsplus.com/tutorials/a-guide-to-the-wordpress-theme-customizer-what-it-is-why-it-benefits-us–wp-32959

You can plug into the Import/Export feature by taking a look at the ie.php file in any of the add-on files.

All of this requires pretty good knowledge of PHP.

Hope this helps!