Here's the system I would propose...it might seem crazy, but it's actually pretty strategically nuanced. It's still sudden death. First there's a coin flip. The winner decides if they want to kick or receive. But here's the difference...On offense, you aren't allowed to try for a field goal and you aren't allowed to punt. So if you win the toss and choose to receive, you run the risk of going 4 and out and giving the other team possession on your own 20 yard line. If you choose to kick, you might be giving the game away BUT if you trust your defense to make a few plays, you might be giving yourself the aforementioned field position. Again, first team to score a touchdown wins, and each possession is either the game winning TD or a turnover on downs.