There is no dervish Kurzick armor. Factions, the game in which the Kurzick armor can be attained, was released before Nightfall--the game that the dervish is in. It's just that NF was made after Factions. No derv Kurz. I wish there was, though. Might look cool.
It would be sweet if they could back design armour for those characters. But alas,i don't think it will ever happen. That's another reason i rarely play NF classes, there just isn't enough armour choice...
dervishes wouldnt look too good being all armored