A question just popped into my head: Does the research you want to do affect your admission decision? Do people interested in going to a field less represented by MD/PhDs but still well within the scope of the physician-scientist goal tend to have less competition?
For example, if you have 2 people wanting a PhD in x and 6 people wanting a PhD in y, are they more likely to say "We'll take one of the x fellows and two of the y fellows" or "We'll take three of the eight"?
Edit:
hatePreMeds, thanks for the suggestion. The program actually looks really awesome. It's in a different direction than I was looking, but some of the stuff sounds like stuff I'd love to be involved with and like the stuff I originally got into engineering wanting to do.