yeah, could be done fairly easily. I need to see one up close to verify what i said, I hate making guesses. what it looks like there is an outer liner that is padded (or it is not only the flap is padded.), and a inner liner that is padded (but I think the top flap may not be padded) and zips into the bag has a lid. Would require a lot of investment the zippers

actually what makes sense now that i think about it, outer bag has water proof liner, the flap is lined with foam to soak in heat and block heat. keeps the bag rest of the flexible.
the inner bag has a base and top, it zips close, and lower part is lined with foam, the top flap of that bag is not. makes it a little more easy to zip both parts together.
They both zip together with two way zippers, they zip apart so you can keep your bag on and take your cooler off and clean it out, the inner part gets a strap. Makes life easier.

that's what i see in my head