I saw this fountain pen on eBay: a Chinese made Hero model 3266 with a 360-degree nib sold by czxwyst for $9.99 included free shipping from China. This pen has a special nib that is divided in 4 quadrants with a cross cut (see the close up picture of the nib below) so that the nib can be written in any position. After filling it with Parker ink for testing, the nib is super smooth and while it has a 'Fine' nib, it was written like the 'Medium' nib of my Pilot Vanishing Point.

The only thing is that it has a non-removable aerometric pump and I don't like it because it's harder to fill ink than a piston converter.