"I have never been dating."
I heard some non-native speaker said it. For me it should be just Present Perfect ("I have never dated.") Because my grammar book says that an absence of some action in the past up to now calls for Present Perfect. And "I have never done it" sounds better to me, more succint. I have no idea how it differs from "I have never been doing it."
I did search in Google, surprisingly, the continuous aspect ("been doing") is 35 times more popular.