Here is an utterly amazing library from Michael S., who easily possesses the most Dune books I have seen! Some of those in the collection he got from The Signed Page, but as you can tell his collecting is wide and varied, from numerous countries and decades:
The Library of Michael S.
Michael: The first two pictures cover maybe 90% of my collection of Frank and Brian Herbert works from 17 countries and all derivatives. Also on the first picture you see 4 b/w photos of Frank Herbert, his wife Beverly and Bill Ransom - obtained from his second son Bruce.
Michael: On third photo there are several limited signed editions and The Battle of Corrin that is lettered (only 26 copies), also Dune by Easton Press have 7 autographs from its contributors.
Michael: On forth photo there are japanese editions and two props - Gom Jabbar from Dune miniseries and Crysknife from Dune (1984).
Michael: On fifth photo there are latest polish editions with autographs of translator and artist Wojciech Siudmak. In Children of Dune even me and my fiancee was drawn by this artist (I can provide additional photos if you like 
On the lower shelf there several books by Brian and Kevin - all double signed and two of them personalized to ABC Weatherman and also you see a crysknife from Children of Dune.
Michael: On sixth photo on upper shelf you see 9 printings of first edition of Dune by Chilton - 2nd, 3rd and 5th are signed by Frank. On lower shelf you see french editions with covers by Wojciech Siudmak.
Michael: On the last photo you see several ARCs from which Legends of Dune and Heretics of Dune are signed and The Winds of Dune have still different cover from the final one.