For the purpose of this power, do horde tokens count as one, so that a whole stack could be placed, or would one token be moved only?

SHADOWMELD:#When Dusk occupies a square of hindering terrain, give him a free action and place him in another square of hindering terrain within 6 squares and line of fire. After actions resolve, a friendly character of equal or lesser points that was adjacent to Dusk when given the free action may be placed adjacent to Dusk but can't be given an action until your next turn.

The stack rules state they can't be carried but makes no mention of being placed, and since they are a character it seems like it should work just fine, I think.

Wait, does it say they can't be carried? I thought it was just that a stack counts as a single character.

The rules state that stacks can't be carried.

Gotcha! Just read it, it's the very last sentence of that paragraph in the rules.