In the continuity of OP's post, I'd like to introduce sup [0], a MUA project written in ruby a long time ago by William Morgan to put gmail functionalities in your console. It has seen quite a success (even creating a fork-for-speed, notmuch [1]). Unfortunately William has left the boat, and sup is now maintained by other people. It's still hackish and has some bugs, but it does the work fairly well. Help is highly welcome !

[0] supmua.org

[1] http://notmuchmail.org/