Okay, I'm gonna cheat a little here. Spectral Motion is an in-demand leader in makeup and on-set creature (practical) effects. They do terrific concept and maquette design work as well. I've posted examples below.
Maquettes



And you can see the rest of their maquette designs here.
Have a watch or a clock nearby before you go on over to the Spectral Motion site. You could easily lose a couple hours just browsing their Fantastic Four design work, or the badass stuff they did for the Hellboy movies. I found myself saying badass so much while looking at their work that I've taken on a goal, to find alternatives to describe something that's cool-looking, rather than trot out the tired "badass" adjective whenever I see something visually striking or arresting.
CONCEPT ILLUSTRATION WORK:



'Kay, I think you guys get the idea.
LINK!
http://spectralmotion.com/elements/homepage.html



