Well, I have seen this done in many of the "full monty" threads, and the occasional "bathroom makeover" threads. I have seen people create shower enclosures using everything from aluminum to stainless steel to wood to the big box store plastic shower surrounds to tile on "light" backer board. It is rare that you see any follow-up on any of these threads so I don't know how many of them develop problems/leaks over time. It helps to do a Google search from outside the forums and include terms like "airforums shower stall rebuild." Below is one such thread:
http://www.airforums.com/forums/f39/...walls-673.html
I am going to have to tackle this in the near future myself, and will likely use a a sheet of that textured plastic stuff designed to be used in custom made shower enclosures. I will aim to have as few seams as possible, and will seal with some kind of "remains flexible" silicone.
good luck!