Iron Sky had a very limited cinema release, I know a few of the guys who worked on it, so DVD would be the best bet.
Lightwave in general these days tends to be used for pre viz work in the movies as opposed to finished shots, an example would be the digital R2D2's in the Star Wars prequels were rendered in Lightwave to check the animation and surfacing before final rendering.
Lightwave still has the best 'out of the box' render engine around and although 11 is lagging in many areas compared to other packages it still excels in others and combined with other elements of your pipeline still creates the best all round end results imo.
Looking at the list of which productions Lightwave has been used in is like a whos who of VFX, with Jurassic Park, Babylon5, Battlestar Galactica, Finding Nemo, Titanic and Iron Man just to name a few.