[Fedora-livecd-list] UDF filesystem for the ISO image?

Hi all, This following might be naive - thanks in advance to just tell me if it is. I used to "convert the ISO image to a USB image using livecd-iso-to-disk. After upgrading to Fedora 13, I thought at first that this conversion could now be avoided since the ISO image can now also be used on USB. But there is a caveat: the filesystem being read-only ISO9660, it is not possible to write on such a USB stick (whereas my previous conversion technique allows that). Now here is the crazy idea: would it be feasible to get the best of both worlds by switching to a read-write filesystem like UDF for instance? Thanks in advance. Cheers, Marc