I feel that you may underestimate the amount of insider trading that goes on in private equity. Remember also, the line between insider knowledge being legal or not is somewhat gray.

I doubt there is an on record scheme with company memos and other communication discussing inside info. It's probably much closer to work friendships and casual partnerships that pass much of this information along.

As long as you can build a reasonable model to line up with the information you get, it's pretty difficult without a smoking gun to get caught.