We're going in a few weeks and are using www.Amisdudesert.com. They have some set trips, but also will custom a trip for you. We're doing 9 days with them and covering a lot of ground including desert, mountains, Marrakech & an overnight with a Berber family. Not super super cheap but reasonable and I think worth the money. Certainly the best we've found and we've checked a few. Worth checking out in any case.
best.

Bookmarking

we also are from boston and will have a week in marraketch (sp) next march....anxious to know what you finally settled on...lets talk: rhkonthailand@msn.com

We went last October and used Mark Willenbrock markwillenbrock@gmail.com He is British but has lived in Fez for years. We were with him 10 days for Marrakech to the Sahara to Fez. Fantastic guide and more than fairly priced.

We recently did such a trip and used a company called roughtours.com They were very reasonably priced. 4X4 good condition. Very good holiday. Camel treking in the Sahara and off roading.

We just returned and had wonderful guide. AroundMorocco with Lahcen Boujouija. I just wrote and posted a trip report with lots of helpful info:

http://www.fodors.com/community/africa-the-middle-east/morocco-travel-advice-2010.cfm

Looking for a tour operator for a one week trip to Morocco end of March. I am contacting Lahcen Boujouija per Rayner's recommendation, but also wondered how Amisdudesert turned out?

My husband and I were in Morocco in Sept and had a great tour guide if you are looking for someone in Marrakech. His name is Mustapha Karroum and is the head of all the guides at La Mamounia, so he is a very trusted guide. Make sure you use a liscensed guide! Many people will come up to you on the street to offer to give you a tour (which is against he law there anyway if they are not liscensed) and they'll just take you to their friend's shops. We only had a guide for one day- just wanted to get a lay of the land since the Medina is a pretty confusing area and to get some history along the way. I don't think you need a guide for more than a day in Marrakech. He did take us to some good shops as well for carpets, lanterns, etc...but just tell him ahead of time if you aren't interested in that sort of thing. His email is mustapha-karroum@hotmail.com

Our family did a two week self drive this past December to Morocco.This trip can easily be done on your own without guides.
We flew into Marrakesh;drove to Essaouria,up to El Jadida to Casablanca then to Rabat. From there to Fez; Meknes and back to Marrakesh. We booked the Marrakesh hotels/riads before we went but booked hotels as we went after that.
Quite honestly,the IBIS hotel chain in Morocco is unbelievable. Hotels are beautiful,centrally located sometimes directly on the ocean and very very reasonable-alcohol is also served on the premises for you wine and beer people!Our family loved Morocco and hope that you have a great trip!

I was in Morocco in May and cannot say enough about how wonderful our driver/guide was. Naim Souhel is not only knowledgeable and professional, but he is constantly making sure you are happy and comfortable. You can email him at hohanaim@hotmail.com
We engaged him through Journey Beyond, again can't say enough. See my Trip Report.

Fodor folks...the OP posted the question in Feb 2010...
we are a bit tardy.