Hi @yolanda211,
Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you with us.
Unfortunately, I am not aware of any premade shower hobs.
They are generally made of brick or concrete and then waterproofed and tiled over.
As waterproofing is a licenced industry with strict standards that need to be followed, I'd suggest speaking with your waterproofer to ensure the materials used are up to standards.
Let me know if you have any further questions.
Jacob
