The ROM-switch solution I had envisioned centered on a custom made circuit board that would simply plug into the two ROM sockets. That custom board would then have two pairs of sockets on it, allowing you to plug in the two 64k ROMs and the two 128k ROMs. It would then have circuitry that would "digitally switch" between the two ROMs by a single button press external to the machine. The switch mechanism could either be momentary or locking, which would affect how the controller on the customer board would have to treat the switch.

Sure, it's easier in terms of "development" to switch a few dozen DIP switches. But its a pain in the back side to do that every time you want to switch ROMs. It's easier to perform the switch with a single button press. But then, such would need to be done when the Mac is powered off. And yet, if it is a digital switch, how would you "easily" power the custom board if the machine is switched off?

So there are tradeoffs that need to be considered. Is it supposed to be "easy to develop" or "easy to use"?