In the past, I think paying for digital work was more about resolution. Here's a preview, now pay me for the full resolution. But I think if there's some consensus among collectors, maybe this will work.
What you're saying about future transactions benefiting the creator, that might be interesting to explore. I thought I heard some galleries have terms that limit who you can sell the art to in the future. Returning some percentage of future transactions back to the artist (or gallery) would be cool, but that could always be added as a feature later, right?
As far as keeping a list, I was never able to do that. I have paintings all over the US and 99% of them I have no idea where they are and who owns them. I lose touch with people. And often the transactions are with complete strangers, do you really want to keep in touch with all these random people? Even if I have somebody's email, I don't want to bug them about my artwork. I gave a couple of paintings to my university and I never had access to the room they were displayed, they could be in a landfill by now, no idea.