I think the usual findings are kind of no-brainers. When blind tests don't find differences in cables, that should be no surprise. Take a 50 foot run of 36 guage wire and use it for speaker connections, that's something you can probably blind test a positive result compared with say a 12 guage wire. But comparing two brands of same size copper wire is going to give a null result. The same could be said about other components that have similar performance levels. Some things are just more noticeable than others. That doesn't mean they sound or measure the same in all characteristics, but there comes a point where most people can't tell, just like a size of print they can't read.

I think speakers are the easiest components to identify in a blind test. There is such a wide range of performance levels and optimizations. Speakers are electro-mechanico-acoustic devices, so even though they have relatively simple construction, they have an impossible job. That's why each designer chooses trade-offs he optimizes for, and it's those trade-offs that expose the speaker and make it possible to identify. Mini-monitors have less bass, so you can tell them right away when compared with a speaker with a larger woofer. Horns are more directional, so they have audible cues of their own, lack of reflections and what not. As long as the differences are pretty large, you can tell them right off. But once the differences become subtle, then obviously a blind test will yield a null result.