Excessive rear tire wear.....?

[rah rah 986]

I am needing to replace my rears for the third time since I bought the car which had good tread all the way around. The fronts are still what the car came with and look fine. I've gotten no more than 8000 miles from a set of rears. It is always excessive wear on the inside. Ive read that this is normal alignment for best tire to road contact. But, I would be willing to trade off some of that in order to get reasonable tire wear.