Many "versions" of WbB On30 also have "approved" kits for changing a "stock" plastic part to actual metal or wood one. WbB does offer plastic cabs with different appearances, of wood or metal, Different stacks, etc. All plastic. Most must be ordered individually at purchase time. Others come with multiple versions of a part.
If glue doesn't scare you, cast accessories can be added to change any brand engine. Many additional scale parts for any train are made in metal/ plastic for those who build from 98% "scratch" already, but in box modular parts would be a plus for me. More so if reversible once built.
