Steve.... I haven't looked through all the discussion threads I have found, but I wondered if you had seen this link.
http://www.edimentals.com/blog/wp-co...ist_070215.pdf
Third from the bottom is the offering of this person tomato seed of Tante Cis. They had 11 offerings.
I don't know who it is, but looks like it might be an offering from the NARGS site of folks.
https://www.nargs.org/seed-exchange
You can look at the past lists and it looks like folks list for this year starts Dec 15th.
I don't have time to hunt through the past lists , but maybe you can and find them and a way to contact them, or see about joing this years offerings in hopes of somebody else having the Tante Cis seeds.