There are a handful of attorneys who get into full-time programs each year (usually not the top programs as bb said).
The thing is the top schools are trying to avoid what I call the Boy Scout Syndrome -- people who spend their professional lives collecting credentials in the mistaken belief that they are always one credential short of getting to the next level -- so they pick up a JD, then maybe an MBA. Oh, and then a CFA, then a CPA, then a PMP, maybe becoming Six Sigma certified, then continue to add more "professional badges" that they can pin on their resumes, like adult boy scouts.
If they get even a hint of Boy Scout Syndrome from you, they would rather go with someone else. Not because credentials in and of themselves are bad, but its the mentality of using credentials as the primary means of career advancement (or even worse, as a crutch) that in their view is career limiting.
You advance in your career by either being exceptional at building stuff, or selling stuff. And you become exceptional by actually *doing* it and getting promoted or recognized for the stuff you build or sell - not by the badges you collect and pin on yourself.
Yes, credentials can help *initially* to open that door a little more, but for most people with JDs and MDs who are looking for a career change, what's preventing them from truly progressing in a business career usually has little to do with the fact that they don't have an MBA.