These are lovely. You should write a book (maybe one for children, and one for more advanced artists) on how to create their own tunnel books. THIS would be easier to reproduce and sell, and would get these lovely books into more hands.

Consider, too, that printing them FLAT may be easier - "some assembly required" books! You might find a publisher that would go for that - remember paper dolls? A normal book with the tunnel book pages, perforated or with cut lines printed, might be easier. Either way, though - this could be a real winner. Look for publishers of other 3D books, like pop-up books. You shouldn't pay to publish - you should BE PAID to publish this.