I just purchased the Ricoh GR D after meeting a guy in New York who was shooting with a hand held flash, it was syncing with the camera wirelesly, I have not been able to be put back in touch with him and am now living in Spain, am yet to receive the camera but want to get a jump on things and have read about the Sygma flashes recommended, it seemed like he had a smaller flash unit, does anyone know how this works and if it is possible with GRD to do this.
Firstly, a warm welcome to joining the GRD family. Now to answer ur question, it is possible to sync the GRD with the flash wirelessly. U jus have to purchase a flash which allows u to set to slave mode, a transmitter which sits in the hotshoe of the GRD and a receiver which u fit either at the hotshoe of the flash or a cable which fits into the PC sync outlet of the flash (make sure ur flash has this).. this will allow u to sync the GRD with the flash.. however u will lose TTL metering and will have to set the flash manually.. hope this answers ur question

Attached is a photosite of a japanese GRD user who uses this technique w the GRD n a nikon SB-800.. the transmitter n receiver he use is known as microsync..one of the smallest i have seen.. but its not going to come cheap

http://www.flickr.com/photos/dos-chin/sets/72057594120624392/