Tiffin builds all of their cabinetry. They have a huge wood shop that builds pieces as needed for each new motorhome.
Here are a few images from the wood shop.
Tiffin buys some of the chassis used for their motorhomes and builds their own chassis for the rest. The Allegro Bus we ordered is built on a Tiffin manufactured PowerGlide chassis. Here are a few images from the PowerGlide chassis shop.