Yes you could have a plumber come to your home and custom build you a shower pan from copper.
However this is very expensive and most likely will not last any long than a PVC shower pan liner
That you can build and install yourself.
A copper shower pan for an average shower stall of 3x4 will cost between $200.00 and $500.00 dollars depending on the plumber and how much he decides to charge you, plus the price of copper at the time you buy.