Okay, y'all...out of appreciation for everything you've taught me, every answer to my iggerant questions, I just have to share this.
http://www.brettunsvillage.com/leather/parts/rivets.htm
Scroll down to almost the bottom of the page, to 5/16s rivets....
described as "looking old"
At $8 per hundred, there's plenty to share. I ordered a hundred.