Thanks all. A quick search of PPRuNE and Google didn't show up any sightseeing operators, so I thought if anyone knows, you guys will!
One of the places we want to see is the canyon (described by some as Oman's Grand Canyon), but we're trying to avoid the long drive. It seems an obvious place for heli tours with such beautiful scenery and perhaps difficult terrain. The local souks are on the list too though!
I really do hope it doesn't get spoilt by too much development - I suspect more people are coming here to avoid all the development going on in Dubai and the rest of the UAE...