Grats!
Got my Karoma yesterday at the same place. I didn't camp but would wake up early and do a circle, and do circles on login and logout. Got her at midnight! As I was taming, a horde passed by and then an alliance, but they didn't interfere. Called my ghost girl Ylva.
Then I decided to check on Madexx - and lo and behold, the green version of him was there! I want the blue skin, so I promptly PMed a friend and now he's got an awsome PvP bud!
It seems that many of us are seing one rare up after another. So maybe the theory "remove a rare to make another one spawn" is valid in Cata zones, too.