I would never go around Dubai in a mini-skirt, unfortunately, cos I'm from London and we don't get much warm weather here so it would be a perfect opportunity, but you have to respect other people's customs.
But, i do wear tank tops-no strapless tops but vest tops are fine, and i see loads of others doing the same-foreigners, expats and native Dubaians.
Shops like Sauce are mainly for Expats, who are wealty non-Dubaians living in the city, who can afford the clothes, and women who lunch-Muslim women are mainly required to wear a black veil, but when women have parties together, the veil comes off to reveal all their fashion-conscious purchases. Women mainly dress for other women in Dubai and many other Muslim areas.
And at night, youngsters go out to clubs just like we do-I can't tell you how amazed I was the first time I visited a club in Dubai and saw them dressed like normal people from the west-I even picked up a few miniskirts from a store called Babushka in one of their massive malls.
They have stores like Kookai, Zara, Mango-for a Muslim city, Dubai is seen as extremely liberal.