An interesting zoom mic accessory for the GH1.
http://gallery.photographyreview.com...123840&cat=558
I asked Canon about similar products, perhaps taking a mic from their camcorder range.
But they have nothing that fits a DSLR hot shoe, the camcorder shoe is different fit and different contact layout.
They suggested going to Sennheiser for the microphone and BeachTek for XLR and phantom power interface to the stereo 3.5mm socket, with monitoring output.