The high dynamic range will come at ISO 50...

Which means you might as well put it on a tripod and shoot an HDR burst. 

I for one wouldn't mind if this was a rehoused G3 with a hardened/weatherproof body and Olympus IBIS. Especially if it did video even as well as a GH1. Even without the video its very intriqueing. Every time I go through my lightroom libraries the shots I did when I was shooting Olympus's jump out at me.  Maybe I just miss my Oly 11-22 but I don't think its all glass I'm seeing.

I say ISO 50 cause I doubt olympus found a way to break the laws of physics and more than 11.5 or so stops from a 4/3 sensor is quite dificult at ISO 160. If you look at the GH1 it has a bit more dynamic range than the GH2 only at ISO 100, 1/3 of a stop to be precise. So if they can go to ISO 50 its not unrealistic to extract a good 12.3-12.5 stops

If it's  12 stops, it's gonna be better than film!
About ISO - in e-p1 the lowest iso is the worst in DR. Pentax k-r does not let you dial iso 100 at all with "hightlight correction", so basically it works the other way around - the sensor must have where to drop sensitivity to. From 50 it's 25, which isn't  something you can see on a digital camera. So, unless you really have some inside information, i would suggest that this business works best at lowest iso plus one stop.