While you look for that "Holy Grail" pen - consider a Pilot Metropolitan (MR out of US). They retail here in the states about $15.
They have a butter smooth nib - at least the four I got from Staples. They only carry medium size but other dedicated pen outlets in the US carry fine as well. The fine will be smooth too - but perhaps not as smooth as you desire from your experience.
They are lighter than my 2 VP's, and are a traditional shape you may find easier to hold.
For $15 you too might be amazed how good a basic pen can be. You see, Pilot has a strong reputation for very well made nibs.
They put well made, smooth nibs in even the cheapest of pens. Simply amazing.
If you like the Metro's nib, the same ones are in the Pilot 78G, and they're even lighter with a screw cap.
Before the Metro had the option to get a Fine nib, getting a 78G was one of those methods to getting a Fine on a Metropolitan. Also as cheap as they are, there's usually little fear to just taking the medium (western fine) nib to some 12,000 grit micro-mesh (a couple of figure 8s should do the trick, just make sure the tines are aligned first) to get that extra smoothness.
But I concur, the M on the Metro I had, and the M on the 78G I had, quite wet and smooth for cheapies, outperformed any of the Chinese cheapies I've used (plus they're lighter).
The problem with the OP though, is a Metropolitan (MR there) is about twice the price in the UK.
Edited by KBeezie, 15 November 2014 - 16:02.