I am still a bit puzzled with the /dev/dm-N situation. I have read the comments in Bug #507461 and Bug #497259 and am a bit unclear why /dev/dm-N shows up.
In F11, if /etc/fstab contains an entry where a logical volume is denoted by something like "/dev/mapper/vg_ryniker-lv_root" then that identification appears when the mount command lists mounted filesystems.
If a logical volume is denoted by UUID, such as "UUID=f46b989b-d781-420c-a064-386c85d7bc67", this mounted filesystem is identified by something like "/dev/dm-2".
This observation may not apply to F12 (sorry, I cannot check that right now); if it is true, this suggests a way to obtain the output format you seek.