Phil Bio-Lube and Pedro's ChainJ come to mind, if you've not tried them already. Both are chain lubes. I wouldn't say that either of them are the best chain lube I've ever used, but they do okay and are both biodegradable, if memory serves.

Certainly different plant-based oils have very different properties. Flax (linseed) oil for example is known to be a highly polymerizing oil, which is why it's used in paints and the like. Good to season a cast-iron skillet, too, but such properties may be either helpful or harmful for different uses.

I'd be curious to see how butter. ghee (clarified butter, doesn't need refrigeration [especially as a lube!] so wouldn't get so funky as butter), or coconut oil might hold up as chain lube...the solid oils don't oxidize and gum up in the same ways that something like olive oil does, and therefore might work better. Refining oils can also change things dramatically. For the worse in food, but might be for the better in this case.

Josh
-- 
Crooked River Recyclery
Kent, O.
 
"All Bikes! All People!"