Opera 10 Beta comes in a QT version, meaning it can “use” the GTK theme in a Gnome environment.
Here is Opera 10 under Gnome using the GTK theme ‘Dust': –
Sexy! (And faster to use than Firefox I hate to say.)
You can find the build you want from Opera’s Linux FTP site:
link since removed
Be sure to select both the correct processor type and QT4 if you’re using Jaunty and want Opera to use your GTK theme!
First off, make sure that you have chosen the ‘Opera Standard’ theme in the ‘Appearance’ menu.
Also in the appearance menu – at the bottom, beneath the theme selector – change the ‘Colour Scheme’ to ‘System Colour Scheme’.