There is a set on the Appleton, WI Craigslist.
It looks like they are for 16" rims.
He also has a set of rear axle weights and a set of 3 pc rear weights made by Rolloff.
Not my ad, etc, etc.
By the way, if someone buys those 3 piece rear weights make SURE he has the little clamping wedges to go with them. Otherwise you can not mount them.