I am reading some tweets about the GH2. Some choice quotes:

"Yet another Panasonic guy said GH2 records whilst outputting a live HDMI feed. I don't believe them!! He said 100% sure."

"Photo: GH2 also has manual audio controls http://tumblr.com/xjej78sno"

"Photo: Official GH2 specs. 1080p 60p with variable frame rates plus 1080p 24p native at 23Mbit. GREAT news!! http://tumblr.com/xjej735nn"

"GH2's 40fps burst rate is 4k res!!"

I see DPReview has a preview of the camera as well, but there is not a lot of technical info, and some of it conflicts with these reports (DPReview says 1080/60i, and it's at a lower bitrate than the 24p mode).

Lots more info to come, I'm sure :)

The preview on dpreview (http://www.dpreview.com/previews/panasonicdmcgh2/) and a video intro:

YouTube - Panasonic Lumix GH2 First Look (http://www.youtube.com/watch?v=nVnUeEdYQrI)

GH2 footage: YouTube - Lumix GH2 Aufnahmen von Bruce Dale (http://www.youtube.com/watch?v=eCxPFga8elk)

Although the footage does show some horizontal banding - as pointed out in the comments. Hopefully this is just some interlacing/processing issue that will be ironed out.

Hopefully it will get a hacked firmware also, to give more control. It seems Panasonic have improved a few things, but more recording control is still warranted. Like higher data rates if you have a Class 10 card - SDXC will be good for future proofing storage options.

Maybe if the next Canon one-upped Panasonic with a quad processor, they might be able to use all their pixels and fix the aliasing / moire issues. Then the higher cost could be justified.

There's several new GH2 videos on YouTube (http://www.youtube.com/watch?v=yQcPlq_9ttQ&feature=player_embedded/) now. Doubt they're from a production camera yet though.

Everything I've read and seen shows it's 60i at 17Mbps. Supposedly it's 60p at the sensor and put into 60i wrapper, mostly due to playback compatibility with all TV's....which if true is lame. However, the GH2 does have a much better codec than GH1, so bitrate is not everything. If it's implemented well, ie: with B frames etc, it may look very good. The 1080/24p mode seems to be more or less confirmed to include B frames which should produce a much cleaner image than stock GH1....and the 1080i codec is unknown at this point.
High iso tests also look much more promising, google around, there's 3200 iso samples out there that look pretty good.

The 40fps burst is only good for one second. Not really sure what purpose that will serve, I guess the odd special shot on some kind of motion might make it slightly interesting....but not really.

There was talk that the HDMI out was crippled with frame skipping or something, but until this thing is released with final firmware, nobody knows.
I'm very interested in this camera, can't wait for proper tests/reviews.

One feature sounds really tempting on the surface, but the wording on Panasonic's site leads me to believe it's not all its cracked up to be.

According to Panasonic (http://panasonic.net/avc/lumix/systemcamera/gms/gh2/movie.html#still-image):

While shooting an HD movie, simply press the shutter button and the camera will shoot a photo with 14-megapixel high resolution as it continues to record your movie. This makes sure that you don't miss those decisive moments with either photos or movies, or both.(emphasis mine)

Which sounds wonderful. But elsewhere on the page, it says

The screen will go dark while recording images. A still image will be recorded in the motion image during that period, and audio is not recorded. (empahsis mine)

That kinda sounds like the stills are recorded as part of the video, not just grabbed separately.. Being able to record video and stills at the same time would be great and negate the need to always have a still camera on hand. I guess we'll just have to wait and see once these start getting into reviewer's hands.

I wonder about stills while shooting video, too. Especially since it has to write to the same card it's recording on. I had another camera that did that a while back and it hiccuped the video when I took stills. :-(

Panasonic says the GH2 can record up to 8 still images during movie recording. Maybe it has an internal buffer it holds them in until you stop recording.

Hope that's true as that will be seriously cool. Since they beefed up the processors it might prove to be a very nicely reality. I already plan to buy one with 14-140 to play with and test and then a second (body or with 14-42 or 20/1.7) as I have to have a backup. Wish it came in red. :-)

Well the AF10, is supposed to be able to pull stills whilst filming. Looking at the GH2 site, it's possible that the GH2 will do the same trick and keep running and give a decent quality 1080 grab. This has 'sort of' been confirmed by a few people who've tried the camera.
Just speculation, but I wonder if their are 2 modes for pulling stills, one at 1080 res, where the camera keeps running and the other at full res, which interrupts recording?