on #17, the question mark on top seems out of place. Maybe it could be on the sides of the box with the one on the left reversed so they look like ears (not black)?
I think 39 without the question marks at all might work really well-- with the hands over the box we really don't need the question marks, and even moving them they don't quite fit right.
46 is the current favorite, and I like it as it is for every implementation except the website. For the website it needs to be more horizontal (with the text to the right of the image). Can we see a version that addresses that? The current logo-free site is at http://www.blindboxes.com