HA for high insert volume

I'm looking for some suggestions for setting up a remote failover
Postgres instance (warm spare). In my situation, the db to be failed
over has a very high # of INSERTS (it does a lot of logging), and it
seems like there might be too much overhead using something like usogres
or one of the replication options. We expect it to grow very quickly to
the point at which a full dump and load is not practical (5-15G).

Are people having luck using something like rsync in this instance?
This document :
http://www.taygeta.com/ha-postgresql.html
describes using rsync, but in the case where the # of inserts is low.

Is that working for people, or is there a better way to do this?
We're willing to consider commercial solutions but would prefer OSS.

Thanks in advance,

John Sequeira