I have had covers and cushions +covers made at Damon in Satwa, opposite Municipality building. Reasonable selection of fabric and but bargain on the price. There is a shop further up the road using the same fabric books and is a lot cheaper, however the end result was not quite so good, although was a large tricky shape but was a third of the price and when I picked up the 2nd cover showed him a photo of the first, told me not to pay!!!!! And was quite amused when I insisted.
You can use canvas material but I found the cheap one goes within a year or 2...you can get it from dragon mart . I did make cushion covers for my outdoor furniture using blackout material. It was a cheap alternative at 10 dhs a meter and after 2 years they are still ok
<em>edited by shaks on 23/08/2011</em>