Looking though my old replies and despite the age of the thread I wanted to add something I just found out. Much like the GH2 shoots great B&W at the hacked high ISOs, the GH1 does as well.
In color, ISO 3200 is virtually unusable, FPN all over the place. You can make it look a bit better by shooting at low low WB 2500K, then grade it up to a warmer color, but it's still very noisy. In B&W if you shoot iso 3200, the FPN is virtually gone and you get a much cleaner image. Over expose it a bit if you can then darken it in post and do some mild noise reduction and you'll get a lot more usable footage than you'd think.
Running LPowells Max Latitude and using the Smooth B&W film setting gave me the cleanest image.
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