Then again, maybe they became more valuable over time because there were enough copies out there to create further interest. Put another way, most photographers will never sell out their editions (if they sell that way) but if they're lucky they might have a couple photographs that do sell out. Answer me this Kevin, which do you think would be worth more to a collector; an edition of one that nobody knows about, or a famous photograph purchased many times over by serious collectors, museums, and institutions?
I'm trying to wrap my head around what you're proposing here, and to me it sounds like you're trying to increase the initial worth of your photographs without thinking about the people who will be buying them, and what their intentions may be.
Murray