Boosting an AI in SP has a slight problem, however: you got full information as to exactly how it was boosted (Pretender design, etc.). A workaround here would be using scenario made by someone else. Also, there is a SemiRand, though this I didn't test personally. And Gandalf's server offers some opportunities for this, including these "coop" games (I'm not familiar with this term myself, but I think this is the same as what you meant) - try to proceed from his signature.
