There's no telling how many variations of patient encounters there might be. The USMLE won't even let you have a watch, that's how paranoid they are. Beyond that, they don't want you talking about the encounters...probably so that no one finds out what a lame test this is.
Anyway, I took it back in Jan and the best resource was First Aid for the CS. I was not surprised by any case I got during the CS, b/c they were covered in the FA.
I hate this test so much. It takes forever to schedule, it costs a grand, and it takes forever to get your results. I worried for weeks about my score.
Take the exam seriously, and study hard.