Hi, thanks for responses. Franz I think you are right, writing that it might be hard to get additional icon set because of the freeze. I would like to avoid installing e.g. icons from uncertain sources. I still remember a "trojan" script found on Gnome Look website and .deb package (if I remember correctly; Waterfall ScreenSaver and Ninja Black).
I think that I would feel more confident, if new icons, themes would be provided with the official Wheezy release. But maybe I am too paranoid? Anyway, If Greybird theme is in murrine-themes package, that's good. I will check it for sure. Regards!