Do JWs have books besides the Bible that they view as "sacred" or "inspired"? I see that the JW website contains the text of a few different Bible translations: KJV, ASV, Byington, New World Translation and The Kingdom Interlinear Translation.

From articles such as "The Bible Really Is God’s Inspired Word" (here) I can see that their view is that Bible is inspired by God.

Do Jehovah's Witnesses have any other books, besides the Bible, that they view as "canon" (e.g. a separate/additional message from God) on the same level as (or higher than) the Bible?
No, it's only the Bible. A full description of how Jehovah's Witnesses determine whether a book is canonical can be found in the entry for "Canon" in the book, "Insight on the Scriptures, Vol. 1."

The only books accepted as inspired by God are the 66 books of the Bible commonly accepted by Protestants.