There is a dwarf in Beregost talking about losing his cloak in Cloakwood to a tasloi. I have never found that Tasloi so I wonder where it might be!

Is it any useful?

In the very first map of the cloakwood forest at the SE corner are a group of Tasloi. One of those has the cloak. What sometimes happens is as you are killing them they become scared and run away to somewhere else on the map.

It's all, right it's a cloak of non-detection.

Isn't there another one somewhere?

see i have the same problem, i continually come across that group of tasloi but they never have the cloak, i scout the whole map and still cant find em, but to be honest once your tough enough to get to cloakwood his pathetic quest isnt worth doing