[meissoun]

First of all, people who are not dancers don't know where these shops are - I had to show them to a friend of mine in Cairo who is a licensed tourist guide!

I haven't been to the UAE in a while but then there weren't any costumes shops.
They only happen to be in places where
a) Raqs Sharqi is a traditional dance (which it is not in the UAE - actually it's even officially forbidden...).
b) there are loads of Western dance-tourists asking for them. Which is for example why they don't exist in Beirut.

Consequently good costume shops can be found in Cairo and Istanbul and apparently very few in some towns on the South coast of Turkey.

MEISSOUN