I admit that besides my idea, the vignette of Weathertop with a "white crowned Witch King in the world of the Ring" fighting with Frodo would be amazing! a great occasion to have a unique aspect of the nazgul unveiled... I may even vote for this one instead of my own idea
"Elves seldom give unguarded advice, for advice is a dangerous gift, even from the wise to the wise, and all courses may run ill."(Gildor Inglorion, LOTR1)
We could definitely need some month with "duoramas", showing two persons in interaction, just to cope with the plentitude of ideas that pop up during the vignette months.
Some of the non-winning ideas here could also spill over into regular M-releases. If the chariot does not make it as fellowship miniature, he would certainly be a worthy centerpiece of the M range for Easterlings, and vignettes have been part of the regular releases since 359, Isildor at the Gladden Fields and 362, Bilbo surrenders the one Ring is imho one of the best releases ever made by Mithril. Pushing vignettes for the regular line would probably be a good move.