I'm an attorney that is heading back to b-school (pending acceptance of course). I do enjoy the law and practicing, but I knew going into law school that I wasn't going to do the traditional law firm job. I wanted to work with companies (or start one) and if I did legal counsel, I saw more value in keeping the company OUT of court rather than waiting to crush everyone that dares bring a suit against us. I think my JD will give me a great base for making decisions in a job post-MBA and it also shows that I can handle the upper level courses.
You seem to dismiss the value of doing a job that you truly enjoy. I'm sure you know some attorneys. Ask them if they would mind shadowing you for a day or so in a deposition and go to court with them if they have hearings, etc. Really examin what it is they do and if you'd like it. 50 years years from now you're not going to be thinking about what you accomplished and hopefully it will be fond memories of work you enjoyed.
That said, I know far more people that went to law school and hated it afterwards than those that loved it. Though the ones that hated it are far more vocal about their opinions!