On the EDK2-devel mailing list, Stéphane Veyret just announced Gentoo Linux for EDK2, including rEFInd application support. Excerpt:

I made a Gentoo ebuild for EDK2. This ebuild transforms a little bit the installation in order to be able to use the product as is generally used a library in Linux. Samples are also modified. I also made an ebuild for rEFInd as a proof of concept.

More Information:
https://github.com/sveyret/sveyret-overlay
http://permalink.gmane.org/gmane.comp.bios.edk2.devel/2446