I also have the 17mm f/1.8 m.Zuiko which is a very nice lens too, but it only has half the hyperfocal markings -there's no distance scale on the focus ring.
The down side of having auto focus lenses I think.
The 12mm m.Zuiko was on my list to get, but when it comes to nightscapes I'm hoping the extra aperture of the SLR Magic will be noticeable. I couldn't justify a Voigtlander (f/0.95) to myself
(not that I've found a real short one either).
Al.