I created an icon replacement for my favourite RSS-Reader Vienna [link]
After unzipping you will find the icon as png, icns and icontainer for use with candybar.
Also you will find an matching unread tag.
To install it, go to your Vienna.app, right click and select "Show Package Contents".
Go to Contents/Resources and then drag "unreadStar1.tiff" into that directory (be sure to backup the original file.).
I hope you'll like it.
I updated the icon, removed jaggies at the top an included an neutral Version without "Vienna RSS" at the side.