Crickett, yes, I have powered every Compact Mac with every other compact Mac. Never for long periods, but simple mods in the power connectors allowed them to power on and function normally. But much more than a simple mod is needed to fit an SE/30 logicboard into a Classic case, as the logicboard is twice as big as the Classic logicboards. And two other major problems are the screen brightness control and sound as well as rear bucket ports.
I have put an entire SE chassis inside a Classic case, but the problem there is of course the rear ports need to be modified, which is easy enough to do, since the Classic's are higher, a new row can just be cut beneath them. In fact all of the compact chassis will fit inside all of the other Macs.

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