Is it hard to shape metal? Custom tail lights?

It is not that hard, if you have the measurements and angles you want bent, a welding shop could do it in a few minutes. All they need is some steel and a break press, I have made alot of things more complicated than tail lights. You should also cut the holes before the metal is bent, it will be easier to get everything even and lined up while it is still flat. If you have a set of torches you could do it all yourself, but unless your good with them it will not look nearly as good as mechanical bending.