Disclaimer: I'm a Gnome user and don't care much about KDE
Another disclaimer: KDE is just a example; the scheme I outline below could likely used lot for other stuff as well (other Desktops like Gnome and XFCE; new stuff like AIGLX was in the FC5 days; crucial apps like Firefox, Thunderbird or OpenOffice; there are likely more examples).
People seem to really want KDE4 out in official linux distribution/included in a released Fedora as soon as it hits the street. I can understand that. But well, seems the KDE4 and the Fedora 8 schedule don't match perfectly (anymore; and it remains to be seen if KDE4 won't slip again, as lots of Open-Source-Projects [including Fedora] do).
Which brought me to the idea: Why are we so inflexible? Why can't we ship Fedora 8 with the old KDE, and prepare a KDE4 in a kind of overlay rawhide repo (as well as in rawhide after F8 is ready) within the Fedora project? When KDE4 ships let some people continue to maintain this overlay repo (and a update repo for it) and create a Fedora 8 KDE4 spin composed from the basic Fedora 8 Repo and the overlay repo -- that should make everyone happy and it not that much work afaics, as it's mainly rebuilding the rawhide KDE4 packages for Fedora 8, putting them in a repo somewhere and make sure packages get updated now and then until EOL of F8...