Slip Cases?

Hi, thanks for answering! I assume you mean a "slip case" (like the pic below) and not a dust jacket. Slip cases are really nice, and convenient for select uses. However they are also really expensive... upwards of $10 even when ordering in a reasonable bulk quantity. There is also the thickness and sizing issue, so we'd need to stock multiple sizes.

I think a great accessory product you could sell for hardcover books is slip cases.
They are difficult to find; usually custom.
Having a slip cover is great for interviews to protect the book from wear and the elements (obviously) and to prevent "perusal" before an actual interview or meeting.