I have found that Jack's Needles, Shuttles, and Bobbins shop usually has needles which aren't standard today. He has been very quick to answer my questions, is very knowledgeable, and ships quickly.
https://www.jacksneedles.com/
The Treadle Lady also carries many needles. Look for her shop on Etsy. She ships quickly and is just a delightful lady. It's fun to watch her videos on Instagram.
I'm tickled pink that you are getting your treadle up and running again!