I think they picked the holiday season as release date for 6.3 cuz it might boost the sales for bryce related content and such. As we all know, the release of even just a minor version creates quite a buzz in the world of bryce!
However, since the new version 7 isnt being released around the holidays, i would guess its going to be at the very least several months later before we get a new version. I wouldnt be surprised if it'll end up being released in the 4th quarter of 2010.

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