I got this recently, almost by accident, but I didn't know it had the databack...
I've seen lots of cameras with databacks... but I've never seen one that has a stopwatch built in to it...
It does the normal calendar (1978 - 1999) or time, too... and it conveniently uses the same kind of batteries for the databack as for the main camera.
Unfortunately, focus on the 50mm f2 is completely jammed. I haven't run film through it to see if the back works, but it all seems to so far...
Pretty cool... though it looks like the kind of thing a real Ricoh fan would like, so I may see if I can find a fan (are these scarce? that bay place doesn't seem to have any) and then look for a plain one.
-Eric