I have, but it didn't really amount to much directly from the rebate.
The Stratosphere had a rebate program years ago whereby they paid back your losses in free play up to $100 after playing a minimum of 30 minutes on any of their machines. As outlined here, I played at higher than normal denominations hoping to either hit something decent or lose the $100 trying. I lost the full $100.
I received $100 in free play and 4 free room nights which I took them up on 4 months later.
With the $100 in free play, I hit a decent bonus round on some slot machine (Buffalo?) and cashed out $325.
At the time, I was more of a blackjack player and ended up leaving with a final profit of around $2700.