Quiet Wave-Creating Machinery -- 2

I'm seeking a specialized piece of machinery to create waves in a waterbed mattress. The mechanism should ideally be a crank and slider, converting circular motion to an up-and-down motion, repeatedly pushing down on the mattress. It needs to run for up to 9 hours each night.

Key Requirements:
- Electric power source
- Whisper-quiet operation (20-30 dB maximum)
- Cord length of 270 inches with an in-line on-off switch
- A combination of metal and plastic materials – Prefer at least one-year warrantee with information on how repairs, replacements etc. will be handled.

Ideal Skills and Experience:
- Mechanical engineering expertise
- Experience with quiet electric motors
- Proficiency in designing with metal and plastic materials

Please provide a detailed proposal, including relevant experience via a portfolio or previous successful projects, warranty implementation, and estimated timelines.