So here's a piece done by Claudio Tolomei which I figured would be nice to share. 3d production in Maya, imported into the Unreal Engine and then transferred this composition into Photoshop to do post. It's a straightforward process, but the results are simply amazing. This is exactly what students whose portfolios are environment-focused, like me, should have along with their fly-throughs and whatnot. It's a strong addition to a demo reel because it shows that you've got knowledge in fundamentals of art- composing a shot, lighting, color, mood, perspective, etc.
You can click on the link to check out the thread on CGSociety. As for me, I'll be preparing the next couple of projects.