The Ubuntu Light Themes branch has been updated a few minutes ago (the changes aren't in the official Quantal repositories for now), bringing some interesting changes to the Ambiance and Radiance themes for Ubuntu 12.10 Quantal Quetzal:

Light Themes Evolved - Ambiance and Radiance - include improvements like an uniform dark toolbar and titlebar, elementary applications tweaks, better scrollbars for applications that don't support overlay scrollbars and lots more. The themes were ported to GTK3 a while back, but they didn't include my favourite "fix": a dark sidebar for Nautilus (Ambiance). This fix is, however, finally available in the latest version.

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Remember Borderless Elementary? It was quite a success and I'm not sure if that's where the Ubuntu devs got the idea from, but an update today in Ubuntu 11.04 removes the borders for the Ubuntu "Light" themes: Ambiance and Radiance, writes Neil Patel on his blog.

The Ubuntu Light Themes - version 0.1.8 was released today (with a bit of a delay - these fixes were announced  a week ago on the Canonical Design blog)  and while it doesn't bring major changes, it improves the menu slowness (it seems the fix only improves the situation but does not completely solves it - see the comments on this post) and fixes bad contrast between text and background.