The leica D Lux 7 and the Sony X100 series both have hot shoes and are both used by many for light weight on the go studio work as are many of the Fuji Ricoh Canon Nikon Olympus small cameras etc. A light weight travel portrait kit may often consists of a small body (ie the brands I mentioned above) and a couple of speed lights (or even a larger rig like the "Quadra's " I travel with) ...anyway I see your point...its just a shame... it would have cost them next to nothing to have included a flash shoe, and it would have made this camera truly "premium"...
I've the DLux 6 , use it with the Pana EVF and am more than happy with its performance so far.
Let's wait for the GM1 to reach then properly test it n see whether its worthy to be labelled as a premium camera.