Staging Database

The company I work for has a client who has expressed interest in having a
staging database for their data. Staging as in they add data, do some
QCing, then push to a database with an identical schema to make it public.
Fortunately, we're not doing that right now, but it's something they may
want later on. So I wanted to at least start thinking about it. What are
some ways of going about it? Some kind of replication set up comes to mind,
but it would need to be on demand, not constant. It also could be as
infrequent as quarterly, if that makes a difference. Preferably, it would
only require one server with PostgreSQL installed, but I'm not ruling out
multiple servers.

Thanks for any ideas.