On the button in level 1, I'm definitely playing A7s with a ton of limpers, as long as the post flop game is rather loose and/or passive. If you get a flush draw on the flop and there isn't a big bet on the flop, or enough people call a sizable bet, you're getting correct odds to chase, and could end up winning a huge pot if you hit it, with that many people in. By the same reasoning, I'd even limp in with A2s. The kicker doesn't matter, as you can assume both the 2 and 7 are probably beat by a higher ace.