Fedora 17 Alpha release (RC4) was declared GOLD[Source].
This release ships Mesa with llvmpipe (and several other enhancements to allow software rendering), this way gnome-shell can actually be run in a non-accelerated graphics environment - like qemu is.
Just fetch - today or the 28th - an ISO of your flavor (live CDs come in GNOME, KDE, LXDE and XFCE) and run it with qemu:
$ sudo qemu-kvm -smp 2 -m 1024 -net user -net nic \ -cdrom Fedora-17-Alpha-x86_64-Live-Desktop.isoSadly qemu's curl support is still broken, otherwise we could just run:
$ sudo qemu-kvm -smp 2 -m 1024 -net user -net nic \ -cdrom "http://dl.fedoraproject.org/pub/alt/stage/\ 17-Alpha.RC4/Live/x86_64/\ Fedora-17-Alpha-x86_64-Live-Desktop.iso"