I had the luxury of attending the Berkeley Codex Fair on the 6th of February
http://www.codexfoundation.org/ and then the San Francisco Antiquarian Bookfair the next weekend.
http://www.ilab.org/eng/news_main_page/San_Francisco_2011.html The Antiquarian Fair had by far the most expensive books, way out of the range of even wealthy collectors or institutions [numerous items over $50K] but most of these expensive items were scarce because of their antiquity [copy of Marco Polo diary, first edition calf-bound
Wealth of Nations by Adam Smith from seventeen hundreds, etc] not because of a self-induced scarcity by only producing 10 copies.
d gray's comment that these items should be treated as works of art is one I agree with. Some of the work in these books [often way more than just a "book'] is extensive - the tree book with cubes of wood is an example. Not my cup of tea - but an amazing blended work of art and science and agriculture! And hand-painted or constructed items
are art, which is really priced by the beauty in the beholder's eye. Not some extrinsic "reality."
At the Codex I saw a beautifully printed book where the author/publisher had invented several unique fonts, wrote the text and drew and printed a four color frontis-piece map in a book all about the history etc of an inscription on the wall of a house in Rome! Beautifully bound, paper, end pages, etc. Cost many many thousands, over 25 thousand, and only about a dozen copies. Beautiful beautiful book that I would love to hold and inspect closely - but it seems a waste to me because the item itself is printed and many could be made, perhaps with less expensive covers, etc so that a lot more people could enjoy the work.
I actually found a few items I could afford at Codex, including a limited-edition letterpressed broadside of a poem by Thich Nhat Hahn with fine complementary illustration for under $25! I treat most of these book fairs as traveling museums anyway; my eyes are much bigger than my shelves. Or my wallet.