I'm not sure what to make of the interesting service offered by PediaPress. You choose a selection of entries from Wikipedia and PediaPress will make a book out of them and send it to you. The cost of this hard copy starts at $8.99 depending, of course, on how much of Wikipedia you want to print (take a look at a sample book). So theoretically you can aim to have a "fine set of modern encyclopedias on your bookshelf" as the door-to-door salesmen of yesteryear used to say.
It certainly enables you to compile your own book on whatever obscure topic you like and be the owner of a one-off publication. I doubt if there's a mass market here but in these days of customisation in everything, why not customise books?