Has the inverted spectrum thought experiment ever been conducted (and if not, why)?
I don't think inverted prism goggles would be a satisfactory way to empirically test the thought experiment. A key axiom of the argument is that there are no physical changes to our brains or bodies; only the qualia have changed. In a goggles design, there would be a clear physical locus of the change (and we might reasonably call this part of your body for the duration of the experiment), so the shift in qualia would have a clear physical basis.