Yeah, you're absolutly right,
I explored the Vlock route, it would have been ideal but unfortunatly there are issues with the voltages options for the Gh2.
It doesn't work.
The big prob being that if you switch to 7,2 V the cam doesn't recognise it in external power. Yes batteries are 7,2 V but if an ext source is used it bloody needs to be 8,4V !! (thanks Pana engineers for closing systems)
12V, the other option, is overkill, the upper limit seens to be 9V according to the most reliable sources, some people use it up to 10v with IMO some potential risks to stress too much the components.
That's why GH2 users are having tough time with the external power, otherwise the Vlock solution would have falled naturally as ideal.