The original "concept" was proven to build an A500 with a Zorro (+5719 chip) slot. For folks wanting a basic Amiga (original) the opportunities abound on either of the *bays; for the "full fairyland effect," the minimig exists. For a better designed advanced original Amiga (A1200) I'd still check the *bays; but the advanced A1200 clone will go, hands down, to Jens.
For those who believe that, "If wishes and dreams would come true, then I suggest genetically altering pigs so they have wings and could fly." If you can do that, then you can build the Amiga of "dreams and wishes."
p.s., Don't forget to get IRB (Institutional Board Review) approval for the former.