I would like to see some things that might be much too big and expensive for a normal toy market. Like perhaps a ferris wheel, though that would probably have a limited audience. Some other things that might have a wider audience:
A large pirate ship, much closer to actual scale, with sleeping quarters below deck and rows of cannons.
The paddle boat that was never released as it was deemed too expensive.
Stocks and gallows. What western town is complete without gallows?
A western coroner with hearse, or even a modern funeral set with a proper coffin, flowers, and modern hearse. Much too dark for kids perhaps, but essential for serious photo stories and dios made by adults.
EDIT: Just noticed Hadoque mentioned larger ships!