So is there a way to enable or install the full version of the free and open source CKEditor in CiviCRM 4.6.x ? 

Looks like the CKEditor Standard editor (see <http://ckeditor.com/demo#standard> ) is installed with Civi (see <http://d46.demo.civicrm.org/civicrm/a/#/mailing/37> ), but the "full featured" version ( see <http://ckeditor.com/demo#full> ) has more useful stuff, particularly aligning and centering text.

I've used the full version on the CKEditor demo site just to center text for a CiviMail mailing. That works, but having the full featured version right in CiviMail would be handy.