I think that would fall under the implementations details for me. It'd be a nice idea to show a listing of all registered unions when going to the amazon.union

I think that would fall under the implementations details for me. It'd be a nice idea to show a listing of all registered unions when going to the amazon.union domain, with further subdomains for specific unions. (xxx.amazon.union, yyy.amazon.union, etc). I don't think this would lead to any monopolization of power.