I would think a good place to look would be the big Portland Antique Show. They have a ton of good western stuff and a few chips scattered about. The problem is that the show is so big it takes two days to see it all. I seem to recall someone posting on the board a couple of years ago that his wife found him a Diamond Jim's Jackpot $25 for a few bucks - it was a $1,500 chip at the time so it is sometimes worth the search.