Sorting Books by Color

A few years ago, in the course of a post on how to sort books, I said, "There are in fact people who arrange books by color" (alas, the link is now dead); I discover from a comment by Doctor Science in this Log thread (for a post in which Pullum answers the eternal question "What does Kreisoppa Tebberley mean?") that the New England Law Library has a search function called "Well, Its Red" that actually allows you to look for a book based on its color. I could have used that back in my bookstore-worker days.
-Language Hat