Your last idea gives me the concept of a piston type thing, but instead of pulling ink, it only moves very slightly to create more room for the air. Not a brilliant concept for production, I will admit, and achieving it is more hassle than is humanly necessary.
Now I have tried the last idea I said I like, which is to add an object to the barrel that prevents filling the whole thing. I have therefore created the "REDUCED eyedropper pen". When the forum allows me to upload photos, i will share it.
Basically, the eyedroppered pen now has a chamber about half the barrel, almost about 2ml of ink. It looks nicer too. I tried it in two scenarios: filled with ink, of course there is no burp. and near empty (a couple drops of ink, lots of air).
In the last scenario, it first performed very well. The next try, it burped four times in a paragraph, but that was a whole lot of air I must give it that. There is also a chance that this particular nib/feed have a problem overfilling with ink, leaving no room for any escape routes.
now where is my upload function?