Some people are now aware of (and using) the nightly Rawhide live builds. To save time and bandwidth, it should be noted that all nightly builds since 2009-09-18 fail to boot at all, on any hardware, and are hence essentially unusable. We are currently looking into the cause of this problem and hope to have the nightly builds working again soon.
Update 2009-09-24: The initial problem was resolved, but 2009-09-22 and 2009-09-23 nightly builds were affected by a second problem with the same result. We hope that 2009-09-24 builds will finally fix all issues and boot correctly, once they are available (which depends on when the main Rawhide compose is completed).
In the mean time, the latest available working live build is Snap3, which is available at the pre-release download page. This was built from the 2009-09-17 Rawhide tree.