Don, first off let me apologize if any of my posts came off aggressive or offensive. I didn't intend that and my posts were not directed at you. I simply am stating that it IS possible to make more dough from existing pizza dough and I believe it is possible to make a starter from old dough.
2ndly, I have no doubt you are an honest and ethical man. I also would never question your results. Your results are your results. Just because you and/or Mark are not successful in making a starter from old dough on your 1st attempt doesn't mean it is impossible either. It just may be that the conditions were not optimize for it. All I ask is that you document for us exactly what you did and the baker's % of starter you used (relative to the total flour amount). Also, I'm an optimistic person and have full confidence both you and Mark will be successful.
I am leaving early tomorrow morning for a week long trip. If you and Mark are successful and I hope you are, then there is no reason for me to run the experiments. BUT if you both are not successful, I will do the experiment once I get back from my trip. I will attempt to 1) make more pizza dough using old dough and 2) make a viable starter from old dough. I would hope for you, Mark, and myself to be successful on the first try but realize it may take a few attempts.
In the meantime (assuming you are currently making dough from old dough), can you tell us how much starter (in baker's %) you used initially to make the old dough? Also how much old dough did you use to make the current dough. This way we can hypothesize if it will work and approximately how long it should take. And I agree with you, no doubt there WILL be a period of inactivity. How long will depend on how much yeast was in the old dough and how much old dough was used.
To make new dough or a starter from old dough, I would personally start with a relative high amount of old dough. So for new pizza dough, I might start with 20-30% old dough. If attempting to make a starter, I would soften the old dough with an equal amount of water and then add a bit of flour to that. Let it sit in a warm place covered (temp of 80's) stir and feed every 3-6hours. I summize it should take off within 24 hours but that may be dependant on how much viable yeast was in the old dough to begin with. If it was well proofed, I can't see it not working.
Here's a bit on SF SD bread from Wikipedia (if that can be considered reliable information)http://en.wikipedia.org/wiki/SourdoughSourdough starter is made with a small amount of old dough saved from a prior batch, and is sometimes called mother dough or chef. This small amount of old-dough starter contains the culture, and its weight is increased by additions of new dough and mixing or kneading followed by rest or leavening periods. A small amount of the resulting dough is then saved to use as old-dough starter for the next batch. As long as this starter culture is fed flour and water weekly, it can stay at room temperature indefinitely.
Sourdough bread is made by combining the increased amount of starter with another new-dough addition, along with any other desired ingredients to make the final dough. The starter comprises about 20-25% of the final dough, though particular formulas vary and that ratio may be higher. This final dough may be divided and shaped, then is allowed to rise, and is followed by baking.
Looking forward to the results. And again, let's keep this light and fun.