Has this ever been done before (Question about Yahoo Answers)?

You do understand the time involved in this, don't you? It is going to take you well over a year to accomplish this. My best guess says you'll lose interest long before that happens.

It may already have been done, though. I don't think Y!A keeps stats on that kind of thing.

Even at level 7 you can ask only 20 questions a day and lose 100 points per day that way. It's a pretty stupid thing to, IMO, but the daily limits have been there only since midnight PDT april 15/16, 2012, so you might very well be the first to misuse YA this way. Very likely Yahoo will suspend all your Yahoo email accounts from participating on YA first.

i am not sure, i have never heard of it before.