I think that the idea of a 'flagship' is a bit erroneous. The Kingsize is the largest (and is available in a flat-top and torpedo) - within that, the standard model is made from black ebonite with the barrel in either black ebonite or clear acrylic. I have a standard kingsize torpedo with a clear barrel (fitted with a 149 nib), and it a lovely pen.
Then, of the kingsize, there was one celluloid special edition (the Flanders Fields LE to commemorate WWI), and from what I understand, a further "King of Holland" LE is due in orange ebonite. The FPN is an LE in pearlescent acrylic. There is also a striated green 'standard model' mooted. All of these, however, are of the same kingsize silhouette.
... there is the CAISO (Cap Actuated Ink Shut Off) which I suppose you could call the 'technological flagship'. I have yet to see one in person (I have, however, ordered one and should be picking it up at the London Pen Show in October), but this is an evolution of the bulkfiller concept whereby the reservoir is opened and closed by screwing/unscrewing the cap. I am sceptical as to whether this will add any practical benefits to the user-operated blind cap seal, but I was intrigued...
Hope that helps.
Edited by mongrelnomad, 09 September 2015 - 13:13.
Too many pens; too little writing.