The Super Zen has what Sugino calls an S3 Cubic Super Smooth Surface and is bead blasted & electrochemical dipped (making them cost about 3 times more than a Zen). They're not easily available in the US.

From Sugino's site:

The S3 chainring is rigid and has less friction compared with the anodized chainring. The S3 chainring can minimize the chain driving resistance and achieve more effective power transmission.The S3 chainring will offer amazing performances at track races wherein the winner is often decided by hundredths of a second. As the abrasion speed is about a tenth of the anodized one, smooth wheeling can be maintained for a longer period of time.