Solstice is a remake of my Autumn theme, but this time it was made to support all resolutions. It's perfect to give GRUB a bit of color for the end of Fall, and onto Winter. The background is from Elementary OS Luna's default wallpapers.

There's a README in the tar file for many common questions and to install the theme, just run the install.sh script with ./install.sh while you're in the directory and have root privileges.