Schematic and layout of PCB for telephone interface board

I would like someone to design and implement a PCB module to interface a Raspberry Pi with a regular telephone line (POTS). (Not VOIP). Design should minimize BOM and costs. I have identified a few potential chipsets for use but you can make suggestions. The module will allow a Raspberry Pi to answer the phone, hang up phone, check caller-id, record voice messages. Interface should be through USB and/or serial port. Ideally, a driver library is provided to run on the Raspberry Pi. An example item can be seen here: [login to view URL] Deliverable includes a working prototype mailed to me in the US, instructions, any necessary software libraries, schematics and design files such as PCB gerber file etc.