Dale other than the body (including interior cabinetry), the frame and upholstery (the sewing part, curtains (the sewing part) ... everything
is manufactured by someone else. That's everything from the appliances to vents to exterior plastic parts. Terry has the right idea, use the web to your advantage and shop for best prices. You'll find model #s and the like on every item.
As a suggestion, use Fusion paint
on any exterior plastic item BEFORE you install on your trailer. Fusion paint
is formulated for plastics and will help with UV damage and extend the life of the product.