There is a story going around the net and it sounds feasible.
It goes like this, allow an individual to take ex-amount of money each year and invest it in a private account tax free (IRA's?) than when they apply for SS the amount accumalated would be deducted off their benefits. It wouldn't cost the government as much to implement.
Would there be an additional benefit for that? People may well not wish to do that if any profit is deducted from SS payments without an incentive.