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.
yes, but in peds, not in neuro. While I'm sure the CHOP peds residency is extremely competitive, if you want to know about DOs in neurology residency, you need to compare apples to apples for it to be a fair and accurate comparison. And as far as neurology goes, from numerous conversations with various attendings during the interview trail, neuro at the "top 5-10" programs has gotten quite competitive in the past couple years, partially due to the addition of numerous fellowships such as interventional neuro and pain, and increased opportunities within the already existing fellowship areas.
While I wouldn't discourage anyone from trying to achieve their goals, it is getting harder each year, even without the outside pressures of increased number of applicants across the board for all specialties, etc.