Suspension Noise problems of the 2011 Jeep Liberty

Brought to dealer for the same noises I've been complaining about for the past 9 months. The old tires were balanced and rotated prior to the second (noise/suspension) complaint to the dealer 5/10/12. Immediately prior to this Jan 2013 appointment I replaced scalloped tires with 4 brand new tires, balanced and I paid for the alignment. I still get helicopter sounding noise at high speed and asked that the suspension which was verified as not the problem back in may 2012 be checked again. A technician went for a drive with me and heard it. The dealership said that two tires were unbalanced. Back where I bought the tires, I had them re-do the balance and align. Still not happy with the same noise. I again brought the car back to the dealer Mar 2013 and I told them to send a repo truck to my house if the noise is not found. I knew I was going to pay for balance/align only this time the tech finally says that multiple parts have been replaced on the same model for the same noise and nothing gets rid of it, the noise was described to me as a "common Liberty sound" and that it comes from the power-train with no remedy. Every time I go in for an answer, I'm offered some other service which "may" be needed. This time it was rear brake pads and rotors. Not the cause of the thumping helo-pad noise, decline.