Seeking info re Miquelrius hack

I have a small Miquelrius notebook, 200 leaves, approximately 4”x6”. I intend to use it and two similar-sized Moleskine Cahiers as my go-everywhere notetaking system. What I am looking for is a cover for the Miquelrius that I can put the back cover into and then use the front flap to secure the two Cahiers. (Think one of those covers that people like At A Glance sell for their products, only a different size.) Oh, and something that doesn’t cost $70-plus, like all of the Levenger products.

Has anyone had this problem, and come up with a solution?

I’d settle for something I could use as a slipcase, as long as it isn’t too big.