I second Craigslist. If there is ever something in particular I'm on the prowl for, I'll monitor Craigslist ads like a hawk.
Oh, and eBay. Searching for "Gossip Bench" on there gets a few hits. I didn't look into the locations as to where they all are being sold from, but maybe you'll get lucky.
You could also hit up all of your local antique shops, and ask if there is any way they could possibly put you on a list, so if they should chance to get a gossip bench in, you'd be the first for them to call.
Good luck!