When I was applying to med school, I was a non-traditional applicant, had not been pre-med during college, etc. so I had never had the input of a "pre-med advisor" during college about the application process, etc., nor did I any longer have access to such an advisor.
I located a local "medical school admissions consultant" over the web & got some very helpful advice from her.
Probably you can locate something similar for residency. I just did a quick google search for "fmg residency interview consultant" and for "fmg mock residency interview" and got quite a few hits with both. (I didn't want to post any links here because I know nothing about the quality/reputation of any of these services & thus would not want to endorse any of them.)
Having said that, I'm not sure whether you'd necessarily need to PAY for this kind of interview "practice". It looks like a lot of those sites had examples of common questions you'll be asked, etc. Why not just have a close friend sit down with you in front of a video recorder (as suggested earlier) and go over some of those questions with you. If you have "friends" or other connections in the medical field who would be willing to do a practice interview with you (maybe one of your letter writers?) you might be able to get a little more medically-relevant feedback, but I think even a good friend or relative (non-medical) could give you some good practice. I really think video-recording ANY mock interview would be a great idea.
(I'd frankly exhaust my "free" resources for practicing before moving on to a paid service; maybe you'll find that you've gotten enough practice and don't need to pay for more. And even if you still think you need paid/"professional" advice, by practicing on your own first you'll have been able to work on the more "obvious" stuff that needs attention and can make the most of your $$ by getting help with the finer details...)
Good luck with everything!
