I think Vimeo is a pretty good choice, as Jambe Davdar's OT commentaries (Star Wars Begins, Building Empire, Returning to Jedi) are up there. However, I think Adywan complained about some of his clips being taken down (though still others of his have been up for years).
If you were really paranoid about their taking it down, I think you could password=protect them on Vimeo and tell us what the password is.