Rated 3 out of 5 stars

Would probably be great if it worked in TB60!

An alternative manual method is to create a user.js file in your Thuderbird profile with these these copied lines from your pref.js where you can manually order them

user_pref("mail.accountmanager.accounts", "account4,account1,account3,account2");
user_pref("mail.accountmanager.defaultaccount", "account4");

Follow the links here for more detail:
http://kb.mozillazine.org/Thunderbird_:_Tips_:_Change_Account_Order

This review is for a previous version of the add-on (1.1.1).