I totally second LeslieG and the CIG.
Board and novelty books are very expensive to create compared to how much they retail for, so there is a very small profit margin. For this reason, you will typically find books that are either extremely simple concept books or similar written in-house or by the artist (so they only have to pay one person, and that, usually very little compared to picture books), OR, board book versions of existing picture books (in other words, the SAME BOOK, just shrunk), OR "spin offs" of existing popular picture book characters (like OLIVIA COUNTS or CURIOUS GEORGE ABC kind of thing).
There are VERY FEW text-onlys bought specifically to be board books. In fact... I can't think of ANY. Every board book I can think of was either written by the artist or editor, or is a spin-off or shrunken version of an existing picture book property.
If you are an artist, and you have an awesome idea for a novelty book or set of novelty books, this is a possibility. OR if you are just a writer and you make a name for yourself (and your characters) in picture books, that's a possibility. Otherwise it's a tough one.