i assume the GH2 alternative is the result of Panasonic offering you a big money sponsorship
in addition to the resolution and format (for the print size you're contemplating) issues, the Panny lenses are slower and GH2 noise worse - not a good combination in the English climate
the 70-100 f4 is great. i wish there were a better choice than the 17-40, but it's my travel lens also. hate to add to your burden, but the 50 1.4 doesn't weigh much (or even the lighter, disposable 1.
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i think it will be a year, or more likely two before the new mirrorless cameras demonstrate their quality and reliability, get menus and deficiencies rectified, and have quality lenses available that will satisfy all but a few professionals as a primary system