[PSUBS-MAILIST] Source for a demand regulator?

On a different subject, does any one know of a commercial source for the type of demand O2 regulator described in Phil Nuytten's paper titled "Life Support in Small One-Atmosphere Underwater Work Systems"? I like the simple bullet proof design and the fact it has been used successfully for years. In an off message-board email with Phil in which I expressed an interest in buying one of the regulators from his company, he indicated that his company could not source the system because it is a small-demand market and because of the high cost of turning them out in small batches. So I am back on the lookout for an off-the-shelf simple O2 demand regulator designed for a one-atmosphere pressure.