My first 70 kill was last week at level 50, because she didn't see my attack coming and didn't react properly:
http://www.vimeo.com/1236541

My second kill was at level 51 when I killed a 70 hunter from the other faction. It took less than 10 seconds and it felt epic. He was assisting a lower-level near Hammerfall and he attacked me first. I only knew he was a 70 much later, because he was a skull and the Armory was down for hours.
From then on till today I saw two more 70s ... and they both ran away before I could finish them off :( One was another hunter(the same one?) and the other one was a priest, who I shot to 40% or so, then he healed and fled.