Here is the Kowa 8mm LM8HC on the Gh1 and GF1. On any of the standard m43 sensors its full coverage.
Note that the GH1 has an oversized sensor 1.86x crop. All other m43 series have a 2x crop sensor.
On the standard sensor, part of the vignette is removed with a corner brighten mask. A very small part is still left and it can be cropped.
Hard to obtain. I took out the rear mount and glued the Super thin C-mount adapter.