There is a theater in Austin, Texas, called the Alamo Drafthouse that is often used for screenings of old cult classics, new movie geek event movies, or sometimes for filmmaker moderated film festivals, such as Quentin Tarantino's QT Fests.
Whenever they have a special screening of an older film, they commission certain designers and illustrators to come up with a new poster to promote the screening. Though the styles have a lot of differences between them, there is an underlying unity that makes me think that there could be something to what they're doing that may carry over into mainstream poster design. I'll start with designer/illustrator, Tyler Stout.
His style of movie poster almost always consists of a massive orgy of floating heads, just piled upon each other among little knick knacks and various stuff from the movie. It's like a big fanboy geekout collage. Packed to the gills with obscure references and frozen moments taken directly from the screen. He keeps everything unified amid the chaose by sticking to only a handful of colors for the whole image. It's a style with a palpable sense of energy and glee for whichever movie is being represented.
If you look closely at the way the figures and faces are outlined, it looks like he's using Adobe Illustrator, or a similar vector-based program to make these images. There are a lot of outlines, which makes everything almost look plastic. Though, the wavy-ness of some of the line work makes me think that he may physically draw a lot of it, and then scan it into the computer for the finished work.
... come to think of it, this all looks like inkwork, now. Jeez. Look what computers have done. Here I am underestimating someone's handiwork just because it looks so precise. "He must have used a computer!" I say. For shame...