Most "Good" Tower shops have a Fiberglass shop they deal with.
What you propose is a large and bulky piece. Shipping can be done, but get ready..$$$$
There are several shops in my area that do Tower work. But there is ONLY 1 I will use.
This shop has some different designed Hardtops. Not just a slab that has camber to it, but has speaker mounts and light mounts....Has wire chases too.