I ran into one just on the West edge of the zone, just North of E Cabilis gate, around the valley area that iksar bandits, footpads, and scaled wolves roam. It jumped me from behind when I was 3/4 hp at lvl 9. It was blue, and I took it down. It dropped the nifty belt, which I still wear at 15.
So, maybe there is a huge level range, but the only one I've ever seen was 5-8. I have no idea what makes them spawn, but keep an eye out for 'em. Good Hunting!
Koriantor
Iksar Monk
Rallos Zek