From what I've seen, I'd pretty much forget about DO at UPenn, UCSF, and Hopkins unless you are top of your class and have like stellar (240+) board scores with tons of pubs. I've seen allopathic candidates with these types of stats not get interviews at these places, especially UPenn (check out the rejection thread).
As far as the link at UPenn goes, that was for fellowships (and the one linked was a child neuro person) which are for the most part, easier to get than residencies.
BUT, having said that, there are some excellent top-tier programs (outside the "top 5"), i.e., CCF, that do take DOs.