Have you considered wallpaper?

I have not seen patterned hardboard, common brand name Masonite, at my local building supply store in a very long time. People use tile to line their showers now. Lowe's still carries a small selection, but nothing floral. Wood, brick, stone, and the one I liked, beadboard.

Well, I painted the top half of the walls a light blue. It took 3 coats but it's holding up pretty good without prep work. The bottom of the wall will be a light grey paneling I found at Lowes. It's called silvertone. The trim will be white. Have it here in my house in VA. in the 1/2 bath and it really looks nice and bright.