There is a teaser trailer for "The Wicker Tree" doing the rounds, anyone else seen it? Not very impressive I'm afraid, kind of reminded me of that Welsh "The Wicker Man" rip off with that geezer from "East Enders" in it. Can't remember the name of either at present.
However if you want to see something freaky and related to the final parade from the "The Wicker Man" check out the short documentary "Oss Oss Wee Oss" from the 1950s. It' a record of the Padstow May celebrations. I've only seen short clips. It has a very sinister feel to it.