Not to mention the bus incompatibilities. 68000 is a 16bit cpu with 16bit bus while 020+ is 32bit. So how do you run a 32 bit proc on a 16 bit bus? Im sure designers figured all this out 20+ years ago. But I havent.

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The Mac LC should be your inspiration because this is exactly what Apple did with it: The LC has a 16-bit bus and it's running a '020. 

On the PC side of the fence Intel released the 386SX which was the low cost version of the 386DX.  The 386DX had a full 32-bit external bus and the 386SX had a 16-bit external bus and fewer pins.  The actual core of the two chips were effectively the same.  (In the 1980s and early 1990s it was a lot more expensive to make a 32-bit system because your bus had to have many more traces.)  I know that for Intel, they solved the problem by using 2 clock cycles to load a complete instruction.  That is, every other clock cycle would either be the "high 16" or the "low 16."  

Since the '020 doesn't have a shorter bus variant I do wonder how Apple made it work.  At least we know it is possible to do.