Patching in a CBM disk drive connection in a C64 case.

As part of some case mods I'm doing for fun, I've found that the CBM disk drives designed to be used in a standard C64 are all external.

But both the SX64 and the C128D have internal drives.

What would be the least engineered way to have a CBM disk drive connected to a C64 case?

I'm talking about something that would keep the ability to use external drives or printers or whatever.

Maybe a sort of middle PCB that would sit on the CIA 2 socket, and below the 6526 chip itself?