I'm running Ubuntu 12.10.  I've got two 27" monitors, both rotated into portrait mode.  If I modify my "System Settings" for "Display and Monitor", I get the correct screen orientations _after_ login.  The KDM greeter is not rotated, and I have to turn my head to the side during login.

It would seem that the correct workaround is to modify /etc/kde4/kdm/Xsetup to contain a line such as: xrandr --output DVI-0 --rotate left --output DVI-1 --rotate right --same-as DVI-0

This does indeed produce the correct rotation, but the greeter is not properly centered.  The theme ("Ariya") specifies the center of the greeter dialog at "50%, 50%", but it appears to have received the non-rotated screen dimensions and thus places the dialog on the correctly rotated monitors at the offset that would be centered in the non-rotated monitors (e.g. hanging off the upper right corner of the actual monitor).

It does not appear that my having two monitors has any significant impact.  I think the problem occurs with a single monitor as well. It's entirely possible that I'm missing something, but my investigation thus far leads me to conclude that KDM is not properly inspecting the current X state.

Reproducible: Always

Steps to Reproduce:
1. Rotate monitors (physically and in system settings if desired).
2. Modify /etc/kde4/kdm/Xsetup to add apropraite xrandr command.
3. Logout and observe KDM configuration.
Actual Results:  
The KDM greeter was not in the center of the screen.

Expected Results:  
The KDM greeter would be in the center of the screen.

I think this might be correctable with a "portrait mode" them that set the position to something like (28%, 88%) but that would be a horrible hack, and probably wouldn't work properly on monitors with different aspect ratios, etc.

My apologies if I've missed something obvious, and this is not really a bug.