Someone commented at engadget that the idea behind the Ricoh GXR is in fact not new. Minolta had a very similar idea/concept in the Dimage EX1.
hmmm... why did it fail again?...
Apparently Minolta only ever created two modules for this camera. Ricoh launched the GXR with two modules as well. Is it just me or there is an uncanny similarity between the two systems? :D