Nowadays HDMI/MHL/Similar is already quite pointless for phone.
But does it make sense to use WiFi between the phone and its other half, over the distance of less than 0.3 mm? Perhaps an optical link might be better. So, I asked for comments. The optical or WiFi link would be needed just because Jolla phone does not have HDMI connector.
http://img208.imageshack.us/img208/7936/a9lt.jpg