I've considered running a campaign to finance a print run of some of our (SE's) books. But the fact is that it's just so easy to find super cheap paper copies of these books almost anywhere. As long as you buy a copy that was printed before, say, 2005 - or from a reputable publisher like Oxford or Penguin - then the edition will already be pro quality. (After that, it's much more likely that you're buying a print-on-demand copy of a raw Project Gutenberg text.)

If we did offer print books, I think the value-add would be making them extremely ornate, one-of-a-kind editions like Arion Press or Folio Society make, and we'd charge a lot for a copy. But even then I'm still not sure the juice would be worth the squeeze, because that's also been done to death... how many more fancy editions of Dracula or whatever does the world need?