rEFIt's development has been halted for a while now; a maintained for of it called rEFInd
is available as a suggested replacement.
I created the theme using current themes/guides as a base, but have not thoroughly tested it. If there are any issues, please let me know and I'll see what I can do. Instructions for how to set up the theme are in the package, as well as instructions for how to set up OS-specific icon profiles (useful for linux distros).
The theme contains icons for the following operating systems:
FreeBSD, PC Linux OS, Puppy Linux, Legacy, Red Hat, Linux, Sabayon, OS X, Slackware, Arch, Mageia, Ubuntu, Chrome OS, Mandriva, Unknown, Debian, Manjaro, Windows, Elementary, Linux Mint, Fedora, OpenSUSE, and Steam OS
More may be added in the future.