I just realize that there is not any images at download.fedoraproject.org/pub/fedora/linux/development/rawhide/[x86_64,i386]/os/
That's because Rawhide media composes are no longer created. Releng should start creating them once F17 is Branched. I believe we are OK with testing just Branched composes in this test cycle.
The rats_install update is almost ready, but it will not work without images. I would like to pick up the task to build the images based on the work James has done and follow the instruction http://fedoraproject.org/wiki/How_to_create_a_Fedora_install_ISO_for_testing if none of you is doing this.
Read James' comment and Adam's ticket mentioned in this thread. If you want to make sure compose_tree works OK and fix any related problems, that's great.