The Nautripolis theme for Firefox is a blend of both new and old designs. You get a mix of Areo and a mix of the Gnome art style too. In the past I have looked at this theme and didn’t really find it that functional – however, after giving it a second look I do have to say it is not that bad.
Here is a little more about the theme from the developer:
Nautipolis for Firefox: Based on icons from art.gnome.org. Includes support for personas, stumbleupon, chatzilla, downloadmanager, TabMixPlus, fission/fusion, forecastfox, googlebar, googlepreview, and many others… To uninstall first make the default theme active (or the theme you want to remove) and then do ‘uninstall’ from the theme manager.
Want to give this theme a shot? You can download Nautripolis from the Firefox Add-ons website.