There has been some illustrations online indicating that Ricoh may produce a cartridge for Leica M lenses. Yesterday DC Watch posted a report from the CP+ Camera and Imaging Show 2010 (Japan) and one of the pictures shows a Ricoh GXR camera with a Leica M lens:
The Ricoh GXR system has interchangeable cartridges that contain the sensor and lens (mount) in one piece (more info available here and here).
