We pulled out a fiberglass shower from our last house. I'll see if I've got a photo of what the walls looked like afterwards (I'm on the road right now and they're on my home computer).

We've bought tons of stuff at Lowe's and HD. A lot of people on GW bash them, but I've generally gotten good service and fair prices (what was too expensive I bought online).

On your cabinets, don't be afraid to sit down with a designer. Even though what you want is simple, they have to "design" it on their computer system (cabinet, door style, finish, along with layout) to generate pricing. They're not high-pressure salespeople, and the process is pretty painless.

When you're shopping for a surround, keep in mind you've got to get it into the room. A one-piecer probably wouldn't be maneuverable into a small space. You can buy surrounds that come in several pieces. Or consider getting a tub and tiling the walls.

Just an idea for you... I went to my local plumbing supply store and bought all of the faucets/shower heads, etc. for a great discount. It can't hurt to ask. I got excellent, sit-down-and-make-sure-yor-have-everything-you-need service. For example, the type of valve you already have in the wall can affect what type you order, etc. They know the questions to ask. If you go, take pictures with you of what you have. Helps a lot! Many items were in stock, and those that weren't I had within a few days.
Lynn