Where can I find containers to dispense bulk chain lube
In my experience, the best kind of lube container is the Finish Line one, or similar. It has a nozzle that can be snapped off easily for refilling, and a threaded cap which covers it all. The "secret" is the threaded cap, which actually presses the removable nozzle against and into the bottle's neck.

Then, I guess there are three ways to use it:


Buy one, use it, and then refill it indefinitely with the lube of your choice (that's what I do at home and in my carry-along toolbag. Have not had any spilling so far, and I shake them a lot while riding);
Find a product that has the same design (medicines, hair products, etc.), buy some, use them, and then reuse the containers. I found the last image I post below looking for "eyedropper bottles" on google images;
Find similar ones to buy off the shelf. I don't have experience with that.


That's what I am talking about (this is the 100ml bottle, there are smaller ones):



The "eyedropper bottles", showing the inner removable nozzle on the second bottle from left to right (with threaded cap removed):