As noted back in 2011, Melville's "travel desk" was auctioned for $34,160 to an unnamed buyer. Now we know where it went.
An article in yesterday's New York Times, Sendak’s Estate: Debating Where the Things Go, mentions in passing some of the objects in Mr. Sendak's collection: works by Blake, Rembrandt, and Goya, as well as some Melville first editions and his traveling writing desk!
For more on the Sendak-Melville connection, see this post (and the comment).