We are the developers of AvatarROM. We have compiled the ROM for hammerhead (Nexus 5) but we don't have the device with us to test. It would be great if anyone can test and confirm if the ROM boots and works properly.
Its a CM based ROM which has support for MiUi themes. (More info - http://avatarrom.com
Rom link - http://s3.avatarrom.com/Nightly/5.0....hammerhead.zip
Install instructions are same as CM - http://wiki.cyanogenmod.org/w/Install_CM_for_hammerhead