Don't think they're going to do a true lid, ever. They claimed the Envy was "lid-like", and that's probably as close to a lid as it's going to get.
the brothers are probably throwing some prototype already, probably not even planned for production but I don't doubt they have done something weird. I mean hell they overmolded a TeeBird so a Lid isn't out of the question at all just not really something there is a huge market for either which I understand. Then again, if they went ultimate route that would be crazy.