Hi,
I used to live in Abu Dhabi, just 100 miles down the road from Dubai, and still visit both on an annual basis.
Reefing has only really 'taken off' in the last few years there, and there are now a few shops in town.
There's a store I always visit in Abu Dhabi 'Reef-something', sorry forgot the name. Very friendly owner and decent livestock.
Prices for livestock in general were cheaper than the UK, but equipment was expensive. They do source very cheap acrylic tanks from China though I wouldn't be too sure of the quality.
As for outlets in Dubai, you could visit the Aquarium restaurant near the Creek Golf Course and ask them who supplies/maintains their tank ?