The Mitchell report basically used a couple of sources, one being Balco the other being Radomski, who cut a deal with the Gov't. Throw in a couple of others, which were know already, and you have a list. Because Radomski was from the NYC area most of the players that were outed where from the NY teams, the same with Balco except the teams where on the west coast.
Every teams has players using some type of performance enhancements drugs, which will come out when the person supplying is either caught by the Gov't, and turns the players in, or a player is caught failing a drug test. The Mitchell report would have been better if there were more sources but except for Frank Thomas and Jason Giambi no other player talked.
As for surprises, well there shouldn't be any surprised about who is using. You can go from team to team and look at each player and see who has increased in size, and done it quickly. Not to mention players who all of a sudden put up huge #'s out of nowhere.
There are a lot more players out there who I'm sure were shitting bricks that their name didn't appear in the Mitchell report but still maybe outed in the future.
What this report will do is make a player think twice before using a performance enhancement drug, though with the money that's involved it hard to stop them, especially the guy in Triple A who just can't make it without it.