Umaterr,
Secondary MDS is hard to treat successfully, so I think it's very good news that your husband's bone marrow blasts and white blood cell count are normal, and that he's needed only an occasional transfusion. If his platelets and red blood cell count are a bit low but not dangerously low, he may be in a fairly stable state and you can afford to wait for further recommendations from his doctors. I'm also glad that his oncologist is talking to the experts at Dana Farber; I'd give a lot of weight to their recommendations.
Of course you'd rather that he be completely transfusion-free with all counts normal, so it's all relative.
I know that you've looked for clinical trials yourself, and there may be none that apply to his situation and for which he's eligible, but if you want to be more sure about that, you can ask his doctors for trials they know of, and you can also call a
patient educator at the Aplastic Anemia & MDS International Foundation. They are quite friendly and knowledgable and may have ideas about your options, including clinical trials.