Kicad is an interesting choice but I don't think you can have multiple instances of the same cell/hierarchal sheet. As you know, that's a crucial feature in the IC world. It's unfortunate that kicad doesn't have a really good concept of cells because it would make sharing of open source designs so much easier. But at least that ability should be available from the IC side. Pull someone's bandgap with schematic and layout and drop it in

Oh, wow. I didnt noticed that. Ok, that's a KO requirement.