For those looking to shoot with GH1 as well as AF100, the Olympus 14-56mm f2.8-3.5 Mark II autofocuses in AFS mode on the GH1 (and presumably AF100 too). The Sigma 18-50mm f2.8 works only in manual focus on the GH1, but is listed to work in AFS mode on the GH2 (and hopefully AF100 as well):has anyone mentioned the sigma 18-50 f/2.8?
http://www.sigmaphoto.com/shop/18-50mm-f28-ex-dc-macro-sigma
It's a lot cheaper than the olympus and a little bit more in the middle of the zoom range.
http://panasonic.jp/support/global/cs/dsc/connect/gh2.html