Well the new liquid cooled R1200 GS has just been announced by BMW at Intermot show in Cologne!
http://youtu.be/bX3r7orw5j8
http://youtu.be/i6I–Q-Akg4
http://youtu.be/qP4XwVdL9ZY
For more information here is a link to the BMW Press Release the new R1200GS should be at Motorcycle Live! at the NEC in November.