@Ind you have tried @fatpig's battery? (I would have tried it already, but I don't have the DC unit for the GH2.) If it really does work, perhaps someone from the forum should contact them about improving the battery to operate for a longer period of time?
Yep this works . I'm using 9v into my coupler . 12v to my Marshall monitor. Been goodnso far but the battery itself is a piece of shit. Switch starts to come off, led light falls inside box, had one just die on me lol but you get what you pay for right? Biggest problem with this solution is mounting of the battery to your rig. You gotta use Velcro or gaffa tape. Lastly I can get about 3-4 hours use with monitor and camera. Without monitor I can record all day. Just buy a few a guess...
if you take a look here at dvxuser forum http://tinyurl.com/3ukfb4j someone claims to be supplying even 9.6v to his gh2 without problems. is this dangerous? or would you say if it works once, it works always?