>I'm a big believer in technology, but I don't think we'll see (no pun intended) invisible machinery in our lifetime.

Such a machine already exists, its called a black hole :-)

All we need is a little furthur understanding of QM. I haven't seen anything yet that suggests that specific photons cannot be isolated an blocked... or halted, or whatever.

If the machine does not reflect light, it will never bee seen.

An equally interesting machine would be a device that can "block" the graviton particle, the particle that causes gravity. Imagine the disruptions you could cause with that!