Any cases to use with existing folio

[Umdterps2002]

I was wondering if in anyone's searches they've seen an iPad case or holder that is similar to a notepad that goes into a folio?

I'm thinking an iPad holder that can slide in an existing folio via that cardboard backing of a notebook that slides into folios.

Just curios as I'm interested in using some of my old folios and removing the notepad and sliding the iPad in.

Thanks