Peja can play the 2, 3, or even 4 in a small lineup.
As for Peja for Artest, straight-up? I would take it if I was Petrie, Artest is EXACTLY, and I mean EXACTLY what the Kings need. If the Kings were still thinking about winning the championship as soon as possible, and not building a young nucleus for the future, this trade is for the taking. But, it's highly unlikely to go down.
IMO, Artest is a better all-around player. He's a hell of a lot better defender, although Peja isn't a bad defender. Artest isn't afraid to take it to the hole, whereas Peja is.
What the kings exactly need is a new coach and interior defense. Artest can only guard bulky guys like him so his defense is limited and his offense is bad.
As I said L. Bird wouldn't think twice about trading for Peja .