Well, it be rumor no more. The time for Plastic Heresy has come. I'm not sure how YouTube video linking is supposed to work on this forum, so I'll just link to the What's On Today article here
where you can see the trailer for yourself.
Incidentally, this is a rumor confirmation of Plastic Heresy, but I wasn't 100% sure where to post it - here, or general 40K.
EDIT - We got pictures of the box's contents
EDIT #2 - We've got an unboxing, in four parts. Behold Part 1
, Part 2
, Part 3
and finally Part 4