Slony and local machine slave..(supernewbie question)

I use a Mac OSX at work. And finally have a running PG install.

So I'm thinking: can I use some mechanism to have my local PG server
(in our premises) as a slave mirror of the main live website server
(at our data center).

Would Slony be the solution to look at? Is this a dumb thought to
begin with or can this be done with no to minimal loss of the live DB,
by just using some small part of the sys resources on the live server
to keep sending some updates back to our local server.

Locally, we can then use the server for testing against almost the
real DB (including testing future versions of PG), then when we need
to upgrade on the server, use this as a master and live one as a
slave, etc? Also serves as a nice backup.

Or am I dreaming?

The reason I feel this may be possible, presuming Slony allows
something like this, is that I have 24/7 broadband connectivity at
about 100 mbps. And I hardly ever shutdown my OSX, just shut down the
monitor or let the system "sleep".

Thanks for any thoughts.