You remember correctly, David. Steve Cohen invented it first, and it was published right in the Magicana column (the issue was from the 1990s, so Jeff can find it in the archives once they're back up).
Also, more recently, Kostya Kimlat did an e-book on the the Z-pad (that's what I call it for short, I don't think Steve or Kostya gave it a name). It can be found here: http://www.kostyamagic.com/products/nocards.php
. Kostya was terrific about the attributions, and I believe he even includes some of Steve's work with it.