My experience of working in Oman is just two days' worth, but I didn't find it any different than being in UAE as far as dress code. Actually in Oman there were somewhat more local women around, working (for instance, as immigration agents at the airport). I wear a nice pair of trousers for most of my meetings when I travel, and that seemed to work fine there. I certainly didn't get any funny looks. I would not worry about it.
By the way, Oman is light years better than UAE as a tourist destination--I highly recommend spending the weekend out there if you can manage it. I did that, rented an SUV, and drove all over the northern part of the country outside Muscat. It was great! No one said boo as far as a woman driving, or driving around with just two other (Western) female companions. I've posted about the experience in some of the Oman/Muscat threads in the Middle East forum.