Referring to that post about expanding it to include anything else 'via your Garage considerations' Wayne, perhaps you can just have a mirror site of sorts? A completely different auction tree for anything not Amiga... this way when I want to search for Amiga stuff I don't need to worry about Amiga Keywords or worry if someone has omitted these words from there auction altogether...
Also, have you run the necessary maths and/or consequences of the potential extra load on your servers if this was to Erupt over night? ;-)