Here is proposed the rapidly prototype development can be done in 4~6 weeks for our team. It guaranty the functions to meet your requirement before go into production. The schedules are: 

1th Week: Requirement confirmed.

2th Week: Schematic reviewed.

Base on our referenced designed we are able to modify the schematic to meet your requirement in short time.  

3th Week: Layout finished.

4th Week: Making the PCB and Mockup

There is no doubt PCB layout must be considered with the housing design at the same time. You will take certain risk If you separate PCB and housing design. A good ODM/OEM partner can do all these jobs well for you.

5th week: Verified function of working samples