This piece is on Ebay now. It is being sold as a “Trimmed Houdini Mourning Card”. To me, it looks-like a trimmed Houdini letterhead that Harry used after the death of his mother. Here is the link to the auction:
I see it has 11 bids in 5 days, so I figured at least a few of you are in the hunt for this. Myself, I’ll wait for the whole sheet to show-up. What do you think of it?