Here's one I did in MAME for a small contest awhile back. Highest score in 2 rounds (I ended up 2nd place I think)...9060....chew on that!

I lost 2 ships on the way down (better to crash on the way down then on the way back up...otherwise you lose the bonus points at the end of the round) and killed off the other 2 at the start of round 3.