One just went for $1125 on ebay. Gunbroker has a second with a couple pieces missing that is about half that with about 5 days to go.
None I have seen look to be in grand condition. If not purchased as a rig, it is very difficult to find the special grips required.
Ideal made a similar holster for the Colt, and maybe S&W:
http://www.youtube.com/watch?v=ZZ7myzGmfIE
Original holsters for early commercial Lugers are kind of scarce and in some instances difficult to identify. Talk about something to look out for at a flea market!