Specialized Transducer Design

We have a project that we are trying to find an engineer to help us with. Please let us know if this might be of interest. We are looking to create a transducer with the following characteristics. 1) A vibrating element which emits a constant tone continuously for several hours 2) Likely cylindrical in shape, no wider than 3 cm and no taller than 1.5 cm 3) Capable of creating >99% pure mechanical sine wave in the 40-60 Hz range at a power of at least 98 dB 4) Able to be run for 1000+ hours (not necessarily continuously) without degradation of pure tone 5) Have no perceptible extraneous noise when placed within an inch of the ear. 6) Be able to produce this amount of vibration using less than 0.2 Watts 7) Robust enough to be dropped without causing damage to the device.