You know, I never thought about it. I always casually stated, to people learning science, that all (most) substances behave like water, they have a solid, liquid, and a gas phase, all depending on temperature, and yes, as hard as it is to melt copper or table salt, it is possible to boil them -- as hard as that is to visualize. But how do they really do that, on the surface of the Earth? Never really thought about it. So one quick Google later:http://www.physicsforums.com/archive/index.php/t-63308.html
And here's some people pondering the boiling point of steel. Some of their conclusions are a little bit off -- as a solid solution, colligative properties should apply, and depress the boiling point -- but, anyway, there are, apparently theoretical physics calculations that will hive you the temperature. And I'm guessing, once you have a theoretical temperature to shoot for, you can get a tiny sample, in a refractory retort of some sort, and get it to that temperature ( in an inert atmosphere, most likely) and maybe detect the vapor by some photometric method.
But yeah, as poetic as it sounds, a bubbling, boiling pot of liquid copper, yeah, I don't think anyone's seen that. And if someone on these boards has, well, just substitute tungsten, or tantalum, if necessicary,