I'm looking to set up a DNS server to do domain name parking. I'd
like it to resolve any domain requests to a particular IP address,
without having to set up separate zone files in advance. Is this
possible to do, and if so how?

I don't want users to have to first log in to the system, and then
have the system set up a zone file. I'd just like this to happen
without any user registration nor action. As long as they point their
DNS servers over to me, it starts working.