Room for all three? They all look the same from my point of view. Amiga as firmware... SOPC. Rather than being separate projects, they should combine them all into a central repository so they can all work together.
If we can do that, I foresee 3 board designs...
A full ATX board, complete with a PCIe slot, PCI slots and maybe even a zorro II/III slot or two.
A miniITX board with just the essentials, since that seems to be the "in thing."
And the holy grail, a replacement motherboard for a commonly found used laptop. Probably one of the Dells.