Generally, I am against this. Getting the 1 book is, believe it or not, a lot of work. If I find that during a specific month two books are strongly requested, I may throw the Chat open to these two books, allowing RRAers to read one or the other or both and having two simultaneous Chats. But this would only happen in a circumstance where there is high enough interest in two books. Any more than two could become extremely confusing and frankly, defeats the purpose of the Book Chat.
New books are easier to find than old books.
For maximum effect of Book Chat I would like as many people who want to, to be able to participate. Backlists are sometimes notoriously hard to find for lesser known or promoted authors. As far as classics, such as a Jane Austen or Georgette Heyer, I'm all for it as long as it can be generally agreed that the books are readily available for everyone to read. So there you have it. I welcome suggestions, additions and deletia.