This idea just came to me from a brief conversion here:
https://steemit.com/art/@romaan-namoor/leda-versus-bacharus-charcoal-collage-drawing-on-large-scale

The idea is simple on the front end.  Add a "Buy a Print" button to posts tagged under original artwork.  Steemit and the artist would get compensated.

Best idea off the top of my head would be to use the Cafe Press API or something like it.  Eventually a private deal could be setup.

I can see my walls covered in Steemit art!