I think the Natami or the FPGArcade would both be a great machines for classic Amiga fans. For me, I'm leaning toward the FPGArcade, because it would be a good learning platform for VHDL. My main interest in things Amiga at this point is running old software. UAE works fine for this, even on my Athlon XP $5 pc. I still like the idea of dedicated hardware.
If you're looking at using an Amiga flavored modern desktop, which I admit is an appealing idea, I think AROS on gerneric hardware is more sensible. Much as I wish AEon well, that A1X1000 is just going to be too expensive. It's going to have the same problem as AROS- lack of moden software that can use all that power.