Currently I own a Nikon D700 (main camera) and a D300 (backup camera). I own a lot of glass for Nikon: Nikkor 17-35mm f/2.8, Nikkor 50mm f/1.4, Nikkor 70-200mm f/2.8, Nikkor 85mm f/1.8, Sigma 15mm f/2.8 Fisheye and Lensbaby Composer.

I'm going to shoot a movie at the beginning of september. It's quite a big production for a hobby movie, with a decent screenplay. Lenght is going to be somewhere between 30-45 minutes. Currently I have a Casio EX-F1 for 720p, but it's not going to be used for nothing else than for "making of videos" and some highspeed-footage.

My options are:

1) Sell the D300 and buy a D300s. Costs about 1000€.
2) Sell the D300 and buy a D90. Costs nothing.
3) Keep the D300 and buy a Panasonic GH1 + adaptor. Costs about 1500€.
4) Some other camera + Nikon-adapter??? K-7?? (5D MKII costs i bit too much...)

I know I'm the only one that can make this decicion, but even still I'm confused. (I can't sell the D300 and Buy the GH1, because then I wouldn't have a good-enough backup body for stills. I do a lot of weddings, so there's the reason for that.) No reviews on the D300s yet, so I'll probably have to wait for a few weeks before making my decicion. But waiting is hard and speculaton a necessity. :)

If you don't want the 5D I think the K7 is the next best thing, unless you just have to have manual control, in which case your only option is the GH1. The video out of the GH1 isn't as good as the other cameras in terms of the "film look."

As far as I know the actual video quality differences between the D300s and the D90 aren't really pronounced, since the codec is the same low quality.

So if I were you I'd be getting the K7 and an adapter (assuming adapters like that exist). But that's just me.

Of course you may also want to stay in the Nikon system.

It all really depends on what you want and how much you want to spend.