What I do is keep two copies of production on my test machine. At 50GB, that should be pretty doable. When I want a fresh copy of production, all I have to do is:
pg_ctl stop -D $WHERE/dev -mi
rm $WHERE/dev/* -r
mv $WHERE/pre_stage/* $WHERE/dev
cp $WHERE/recovery.sample $WHERE/dev/recovery.conf
pg_ctl start -D $WHERE/dev
tar xf /mnt/something/latest/base.tgz -C $WHERE/pre_stage &
It takes anywhere from a few seconds to a few minutes, depending on how much WAL log has been generated since the last base backup was taken. The last step of replenishing the pre_stage takes longer, but it doesn't matter since I don't have to sit around and wait for it to finish.
Of course this requires you to be using log archiving on the production machine. I would be doing that anyway, though.