Well, the seller I posted above has 21000 feedback. He's probably not a deadbeat.

Yes, these SCA drives seem to often lack on board termination. So,as you mention, a little bit of circuitry would be needed there on the cable. I think that there is a right-angle SCA connector available. One could use that, thus putting a circuit board parallel to the drive. If there's a little room at the connector end of the drive, one could probably whip up a little adapter board with the termination on it and install it at the end of the drive.

As I mentioned, I don't have any PowerBooks, but if you give it a try, would you please post back here. I would enjoy the project vicariously.