I just had to rebuild my USB key for a generic install (got to do that for a drive to send with the system back to the OEM for repair, y'know). This time, I used unetbootin, which took a while to build the key, and worked *almost* well.
The two annoying hangups: it took a *long* time to extract the packages and put them all on the USB key, looking like a repo... EXCEPT that during the install, anaconda *demands* the .iso. I went back, deleted /mnt/usb/Packages, since it's only an 8G key, and just copied DVD 1 onto it. anaconda stopped, asked me where, I told it, and it happily went on its way.
Then, it doesn't give you any kind of default grub.conf
Oh, well. Drive's built and boots.
mark