There are many large manufacturers capable of manufacturing and assembling in-house, and there are many more capable to do the assembly level and then sub-contract the part manufacturing to a network of specialists.
The choice of supplier often comes down to the required manufacturing processes, volume and value of business, cost vs quality requirements, and relevant product experience.
The choice of manufacturing processes depends heavily on the product geometry, choice of materials and volume of production.
I would therefore need some more information on the product geometry, product specifications (cost vs quality vs performance priorites) and the intended production volumes.
What I can offer is product industrialisation / design for manufacture, introductions to appropriate Asian suppliers, supplier management, production readiness assessment, and product quality alignment. See www.jefmek.com for further information.