I did a simple experiment yesterday and want to throw this out to you to think about.
I made a small electrode out of 4 stainless wall switch plates, immersed it in tap water and checked the resistance. It didn't measure stable, but after several seconds, was at 600 ohms. I then added salt to the solution, and found the resistance to be 400. Then I added bleach and the resistance went to zero.
I knew that I couldn't run an electrode with 0 resistance, so I installed an automotive tail light bulb in the circuit. I tested the electrode in each of the 3 electrolytes, and seem to have the following conclusion. The HHO is produced by the passage of current through the electrolyte, apparently in the same or similar amounts regardless of the resistance of the electrode itself. EVEN THOUGH THERE IS NO RESISTANCE, GAS IS FORMED.
(I took a tip from Michael S. Johnston, whose work I found on the web, when he suggested that we think of the electrolyte as a "liquid wire".)
Now I am thinking that if the electrode uses NO current, but passes all of it through to the load (bulb, resistor, etc.), what is to keep you from connecting as many electrodes as you may wish in series, generating gas from every one FOR THE SAME WATTAGE?

I know. This sounds way too simple, but just think about it for a while. I expect to do further tests before long.

No offense, but I don't believe that the circuit through the water/salt/bleach mixtures has zero resistance. How did you measure that? If electrolysis is occurring, then work is being performed to break the hydrogen-oxygen bonds in the water, and this work must come from the electrical energy you are providing. The energy provided by the electrical circuit to perform this work is simply I^2R (current squared times the resistance the current is operating through). If R is zero, no work is performed by the electrical circuit, and hence elctrolysis can not occur.

I checked the resistance with a multi meter and it was 0. When the current was applied, gas formed. I haven't gotten to the part where I can test for volume @ amps. The amps can be controlled readily.
All discussion will be welcomed.
I can't see how the 2nd law of thermodynamics applies to this. The electricity is not endowing the hydrogen with energy, it is only breaking the bond between the H and O. As long as we assume that no efficient way to do this is possible, it will not happen. Let's try to think outside the box and see what we can come up with.
I have an idea or two, but want to hear from some of you first.

UPDATE: For anyone interested in this subject, I found 2 US patents for HHO generators.
Go to USPTO and search patents by number: 4936961 & 6126794