Not a bad idea, those cookie sheets/muffin pans, etc. are a pain to store. Might have to build it from scratch but not too complicated. Makeover an old wooden magazine holder to take control of your cake pans, pizza pans, muffin pans.
This is a perfect combo of my two favorite ideas for that space under the stairs leading to the basement. A reading nook AND book storage and shelves . assuming that there is enough space for this there.