Option on `postgres` CLI to shutdown when there are no more active connections?

Hiya folks,

I'm a bit of a newcomer when it comes to PostgreSQL, so I apologize if this
is
the wrong mailing list. Anyways, my two questions:

1. Is there any interest in adding a command line option to the `postgres`
CLI
that shuts down the PostgreSQL instance once (and optionally cleans up
the
data directory) once all connections have disconnected?
a. Alternatively, I wouldn't mind accomplishing this via the single-user
mode if it could accept the binary/wire protocol in addition to the
current text protocol.
2. Are there plans for having any additional table access methods beyond
`HEAP`
shipping as part of Postgres? I'd love to have something that's purely
in-memory to bypass the tempdir dance that I'm currently doing.
For context, I'm trying to make it easier to test our application against a
live, actual PostgreSQL instance and make the experience feel a lot like
sqlite's embedded/in-memory workflow. Today, we've gotten really great
latencies via test transactions, but I'd also like to ensure that there
aren't
any orphaned Postgres processes at the end of a test run or without
requiring
the user to start an instance of Postgres prior to running the tests.

Warmest regards,
David