This got me thinking to books in Japan from when I visited last year, and checking out the bookshops there. There it seems the format for books is much more common and identical - smaller format, but all of the books were identical vs. varying sizes of Western paperbacks - obviously still the coffee table/art books, but for fiction much more standardized. So much so that it's not uncommon for longer books to be spread across two or three different books - far more practical as anyone who has read War & Peace, or Jonathan Strange & Mr Norrell might be willing to attest. I almost sprained my wrist reading the latter on the train to work...
I must ask my wife about that one, as it may be that was just my impression on first take, but I do know several books she has read in Japanese have been across two separate volumes, including Murakami's 1Q84 and even Dan Brown's The Da Vinci Code. Also Graham Swift's Waterland was across two books if I recall correctly... Japanese kanji/hiragana/katakana may have something to do with it also, maybe taking up more space, but possibly I'd have thought that the kanji being mostly ideograms take up much less space than the Western alphabet.