Yeah I've played around with flohmarket before, and I think it's a great idea. I'm willing to casually set up an instance if there's real interest in using it. People in Vancouver love to give away and get stuff on classified ads sites, so if enough people know, I think it would work. The version I fiddled around with was the one before CAPTCHA was implemented, I need that to avoid spam.
Main thing is interest in people using it. Get my comment 100 upvotes by Sunday and I'll start working on it.