there's one book by Kaplan called MCAT 45 (i don't know if they still put that out)... the questions are as tough as they get, and really, much harder than anything you might see on the real MCAT. but as i see it, you'll be better off with some tougher questions (which may stimulate you to study), than easy questions (and then be shocked by the real MCATs); certainly, if you can handle these questions with ease, then the MCAT would be a breeze. this book only has problems, no full length exams though.
i'd suggest getting something like that, and also something more general (i.e., easier) with lots more practice problems. when it comes to standardized testing, practicing is key. i haven't seen many test preps for MCAT that just offers a lot of questions; usually, it's maybe 2 full length exams plus 200 more practice problems, so you'll likely have to buy a couple books. also, the old exams that AMCAS sells are great too (try to get the more recent ones, because they'll be more indicative of the current MCAT).
