I do not know about the PS2, but I remember there being mod-chips for the PS1 that only unlocked region. In other words, pirating was not an issue. This chip only allowed US/Japan users to play Japan/US games. Which is no different than unlocking the region encoding on a DVD-Rom (provided we can still talk about that). The problem with the chip was user-ignorance... for one reason or another some people believed that the chip tranlsated the games into English as well
As far as where to buy a REGION-FREE PS2
NOT a PS2 that allows pirated games to be played (I know you said this, but I don't want to get banned/post removed over this.) Places that import Japan PS2 games usually have solutions for you.
Banti