Hi,
after some lengthy debugging session :-( I have found that it was not a rawhide update but system-config-network which has caused my IPv6 tunnel to fail. Just starting this application and changing the configuration of my eth0 device caused a line reading "TYPE=Ethernet" to be added to my /etc/sysconfig/network-scripts/ifcfg-sit1 which in turn caused ifup to call ifup-eth instead of ifup-sit. I have created a bugzilla tracker for this: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=137898
Tom