Sodabob, was the discussion on Oso-Grape being purchased by the Grapette Company settled? Or was that a regional thing only? I saw where you addressed this in my post 2 years ago! Better late than never to check in!
Not sure if you are still on this hunt, but I've acquired nearly 20 o-so grape and o-so beverage bottles, and I have 2 bottles that are "So - grape" with "The Taste Tells" slogan on it. In fact, I've got about 5 or 6 different styles of the bottles that came in an o-so grape crate I purchased in Michigan's upper peninsula a month ago. If you are interested, I can try to post some photos and describe each bottle type. I'm not a bottle collector, I just like to buy and sell cool old stuff