There's No stetson, but much worse than that:
A man, a panama works;
Pan, a panama irks.
With his goat-horns, the hat won't sit flat.
A man, a panama., and
A man, a Pan — a panama.
The reader may note that both A Pan, a panama, and To a goat fall short of palindromic status.
It is surprising to realize that the Panama hat was never produced in Panama, and represented an adaptation of the Ecuadorian hat that was imported to Panama and promoted to visiting Europeans.
That big project, if final
(The acclaim being mine'll),
A palindrome plain will explain.
A man, a plan, if final — Panama;
A man, a plan; if A, final? — Panama;
A man, a plan, if B, final? — Panama; etc.