While opening up an off-shores bank account is easy, hiding the assets is difficult. All is well when your money stays in the bank, but you don't hide money to keep it hidden, you're going to want to spend it. That new boat you just bought with all of your tax savings... that gets registered to you, the down payment on the house mortgage... that's in your name. When the IRS sees that you can afford a house/boat whatever have you, and see that you report little to no income [well let's just say] it's safe to assume that your lifestyle exceeds your income... Audit anyone? Thus why, with an off-shore bank account comes, off-shore trusts/foundations/corporations. You run the trust/foundation/corp and the entity that you operate owns the assets. It's not illegal to pay yourself an annual salary of $1 per year, just ask the co-owners of Google. And since all money the trust/corporation makes is over-seas, you don't have to worry about how you'll justify writing off your gas expense for that big yacht
P.S. Consult a lawyer who has experience in off-shore trusts, the tax savings will more than cover attorney fees.