With no research and no significant clinical experience, I would basically eliminate every single "top" school on your list.
(read: NYU, Stanford, Baylor (which has IS preference for Texans), Case Western, Brown, JHU, Harvard, Cornell, Yale, Columbia, WashU)
Your stats are a dime a dozen at those schools, and despite your non-traditional status, I don't think there's a lot to elevate your application above other individuals with similar / better stats and more involvement in research/clinical activities. You have to realize that a lot of the top schools you listed are at the top because of the amount of funding that they receive from research grants, which means that most of them hold research in very high regard when evaluating applicants. The applicants who do get accepted in spite of limited research often have very diverse and intense clinical experiences that set them apart from other qualified applicants.
However, just numbers are still competitive for those schools, so if you have some URM status or if some part of your application is outstanding (which you haven't elaborated upon here), perhaps you'll still have a shot. The medical school application process can be a bit strange sometimes, so who knows. Perhaps you'll come back in a year and rub it in our faces, but I don't think the odds are in your favor.
tl;dr:
DON'T WITHDRAW. Take a look at the applicants who applied to HMS, JHU, WashU, etc. on MDapplicants.com. When you see the type of people who get rejected (without even an interview), perhaps you'll see what I'm getting at.