There's really only one answer to SS solvency down the road, and that's to create budget surpluses today, right now, and on into the timeframe that the general fund will be required to begin paying back the SS trust. If the SS obligations were the only federal debt, the whole thing wouldn't even raise an eyebrow. It's really other debt, exploding under Republican stewardship, that threatens SS and the solvency of the govt itself.
Anything else is just smoke and mirrors. Bush and his advisors know it full well. Their plans are to split the people into two groups- those on private accounts, and those on the current system. This fatally weakens the current system, also provides a strong "us vs them" situation that can be exploited to sell out on the trust, cut benefits, end that most hated of all New Deal programs. In the meanwhile, of course, they'll continue to create massive deficits, financed in part from the trust, cut taxes for those at the top, and to shift the burden down the scale. Push it off on the states, whose tax structures are regressive. Bring in a national sales tax, and/or a VAT. Raise excise taxes. Raise "fees" for everything.
SS will become just another regressive tax, those who've paid the most into it for 45 years or so will get left high and dry. Those who've gained the most from current fiscal policy, the top .01%, will rule supreme over a third world backwater, which is the ultimate goal of Rightwing Ideology, like it or not...