Based on what your saying, I would suggest moving the ball up in your stance. You may not be able to change your swing too much, but you can move the ball forward.
Your downward blow is what is imparting the backspin, so if you can move the ball to a point in your swing where you aren't impacting the ball at such a severe angle, you will probably see a lot less backspin.
Another idea is to pretend you are hitting driver like the old school guys where they would intentionally hit down on the ball -- almost like an iron, (see Ben Hogan). You will lose carry, but if you embrace your swing, you may actually gain some distance. There is nothing wrong with poking line drives 265 if you have that shot under control.
Also, for what it's worth, the G series Ping drivers impart significantly less spin than most other drivers.