WebUpd8 reader Nasser Alshammari sent us some nice Kupfer monochrome icons that go well with the Ubuntu Ambiance and Radiance themes. He writes:
The only side effect of this is that it'll replace the colorful logo in the menu entry and in the "About" dialog of Kupfer. So until this issue is solved and for all the monochrome fanatics out there, they can do it this way for now.
To install them, replace the ~/.icons/hicolor/scalable/apps/kupfer.svg icon with one of the icons below.
Download Kupfer Monochrome icons
Many thanks and credits for the icons and screenshot: Nasser Alshammari