This is really starting to get ridiculous, who needs a 1200 mm equivalent in a body that's impossible to hold still??
Superzoom compacts have moved away from usefulness to marketing gimmick IMHO.
Got one here to complement 5D3 and 60D. As Mt Spokane says, not very ergonomic but light, inconspicuous, pure fun. I use it 95% of the time at 1200mm handheld.
My girlfriend has a Panasonic Lumix FZ-50 which has a 12x zoom and 35 - 420 mm equivalent and is f/2.8 - f/3.7. It takes fabulous pictures given enough light, but so far the 420mm equivalent has been enough reach. What's lacking in this case is more wide angle, something that she's missing a lot. So we're actually looking at something new.
The FZ-200 looks great, 'only' 24x optical zoom (25-600mm equivalent) but it is full range F2.8!!! What's missing is the manual controls of the lens that the FZ-50 has. That really was/is a special superzoom camera.
I have an FZ-50 too and I love it- if it wasn't so noisy I'd probably still be using it more regularly. It's got better ergonomics than entry level DSLR's. Although the LCD seems so TINY now.
I know there's probably physics involved blah-dee-blah but I really can't fathom why there isn't even a 1/1.7" birdge/superzoom (or even better, something like Nikon 1 series). Once you get past the miniaturization constraint of most point and shoots, it seems like there would be a way to get something reasonably sized.