Race...great idea about unsold images and I like the name Cobweb Images. It congers up old dusty out-of-the-mainstream stuff you might find in am attic in a long abandoned house. I've got loads of them also but no desire to put any more work into them. Do you accept donations? How about exclusive donations?
The term Cobweb pages is pretty old. (hmm, maybe that's appropriate?) I started calling pages that are created and seldom or never updated "cobweb" pages.

People start things and then they just sit and gather cobwebs. I know of a site that's ten years old that still says coming soon on it.
I don't know what to call the new phenomena which is pages that come up near the top of searches, but don't exist anymore? Many will take you to some generic landing page full of ads, but some just get you nowhere to a missing link on the host, site not found. Hey wait, aren't people trying to find ways to get into the beginning of the searches, and here we have pages that are, and don't exist.
OK if I get around to starting my own site, (beyond the dozen or so that I dabble with now) I have no expectations that anyone will find it or buy from it, but what the hey, I might as well create it anyway? I'm not giving up the concept, but it's not the motorsport site which would be much easier to justify. Motor Racing, low demand and it's well covered by Getty, Corbis, and LAT. Could be that a mid or micro site could get into that, but I doubt if there's a strong enough market to support a business. All kinds of legal wrangling and access controls as well.
I started a sales site for some products a few years ago. Never got past, testing and planning. Now and then someone finds it and buys something. Last time I think I lost money because the shipping was more than the profit. Really short margin.

Yeah, that's the ticket. People can put images up for sale and if they sell, I pay nothing in return, which will go perfectly with the no marketing and no promises. Unless of course it's actually a profitable sale. Mark this site, labor of love, not for profit... However everything would be On Demand, no accounts, no subs, no nothing. You want it, you pay, you get it. Down and dirty, simple.