On fisher, both the beta release 5.59 and the rawhide 5.61 seem to be broken with respect to runlevel 1 behavior. Issuing an 'init 1' from runlevel 5 shuts down all services and prints a message to the effect of 'telling INIT to go to single-user mode' before hanging. After a few seconds' pause, disk activity begins (no output to console) and gdm starts up again. Very strange. 'init S' still seems to work.
This was hacked around in a later initscripts release. AFAICT, it's a kernel problem.
(basically, remove the 'exec' from the last line of init.d/single)