Network Favicons is a simple WordPress plugin that allows blog owners on a multisite network to upload a favicon to the root of their theme’s directory and have automatically be used as the site’s favicon. This requires a one-to-one relationship between blogs and themes, but that could be as simple as creating a child theme for the favicon if you’re already using the same theme on multiple blogs.
I made the theme for my new hosting network, network.joshbetz.com. This is where I’ll be hosting future client websites and I needed the ability to use custom favicons instead of just having my own favicon displayed on every blog.
Note: If no theme is available in a theme’s directory, the site still just use the default one provided at the domain’s root.