A fast dial icon using font Rosewood Std. I use this icon for the back to fastdial button on my folders.

Fast Dial logos for Fast Dial (Based on the logos created by k-dash).
They look better on dark backgrounds.
I don't know if there is a specific font for FD so I used my favorite font: Babylon Industrial.
I normally use these logos on every folder page and set the shortcut to chrome://fastdial/content/fastdial.html so I can return to the main FD page quickly.
You better use the transparent ones, the ones with black backgrounds are only for illustration!

UPDATE: I added better resolution ones based on the bigger logo by mafi0z, I kept the old ones to show the difference.