Meet the Chin Rest Arm by Thanko: an office gadget that helps you maintain proper posture at work and even get some rest. Its clamp attaches to your desk while the hand keeps your chin up and supports your head. You can adjust the hand and arm sections to a range of positions. The hand is made of soft materials, so it does not make you uncomfortable.
This is yet another interesting Thanko product. What do you think? Worth a shot?