Do you have links on articles on how many books are needed to make living and how much of a living it might be expected at median and high ends? I'm interested in the subject and your offhand comment makes me hope you have more insight into it than I do.

If you’re interested in kindle self pub, there’s a pretty vibrant community on the kboards (kboards.com) forum. Tons of info on producing volume as a marketing strategy but people are definitely making a living. It’s not my approach but I’ve certainly considered it.