How do you manage to use fixtures creatively?

Thanks for the tips… That’s precisely the point I’m at, but I’m either missing completely something, or dreaming of something that can’t be done.

For instance, I might want to make some square lights slightly trapezoidal, or to make them stand out and not being glued to the panels (see for instance JFM The Unicorn Company to explain what I’d like to do without understanding how to do), or even to do something as basic as including the badge in the front grille (http://i31.servimg.com/u/f31/15/41/34/72/captur48.jpg)…
Even managing to have the mirrors set up so that they seem usable is something of a challenge (they snap to the bodywork and I haven’t found how I can do something else than having them at a 90° angle from the bodywork)…