I second the Craigslist sentiment. Download one of the Craigslist apps on your phone and add a search agent for "swisher".
I was looking last summer but when any roughcut mower was posted it was quickly snatched up. With the app, I was also able to find a yard sale where they had a 44" roughcut swisher as soon as it was posted (plus you might overlook it because the word "swisher" was buried in the text). It wasn't running (but due to minor issues).
I paid half of a new one.
I spent about an hour draining the gas, oil, changing the plug and putting in a new starter switch. It works great! I can't recommend it more.