I would also recommend SummitClimb.com. while I havent used their services, yet, I do know the owner, Dan Mazur (who is currently in Nepal climbing Ama Dablam), and he has a great attitude about helping others and is also very flexible in the trips that they run. you will be on their permit and customize your trip to use, or not use, their tents, cooks, porters, guides, etc. but one thing they will have onsite that is a great option to take advantage of is the gamow bag, to treat altitude emergencys. check them out, and as others have said, just start talking and asking questions of the guiding operations and see what they tell you. good luck!