Not sure if anyone is interested but I have just pulled together a quick proof of concept for an MQTT client that works with IoT Hub, including support for device twins. Anyway, the code can be found here: GitHub - networkfusion/NetMfMqttClient: An MQTT client for .Net Micro Framework compatible with Azure IoT Hub
It seems to semi work with the emulator as well (minus all of the gadgeteer related code) but seems to suffer from the known emulator SSL bug (although seemingly not as bad as AMQP.Net Lite).