Four books due out from Hesperus in the middle of the year (which probably means we'll see them some time in 2012, given Hesperus's recent track record*) are their Brief Histories of various forms of literature. Every cover is made up of a shelf of relevant books, but every book is both a fake and a pun (and there's a nice range of fake publishing imprints in there, too).
Among Hesperus's other allegedly forthcoming titles, I especially like this cover.
* I have about a dozen Hesperus titles on order, most of them scheduled to have come out in late 2008 or during 2009, and none of them yet to see print. They do great books, but you do have to wait a bit to read them.