Cast concrete shower pan and galvanized walls make a great bathroom combo for a rustic modern farmhouse.
So rustic -- great texture and coziness.
16 Homely Rustic Bathroom Ideas To Warm You Up This Winter
Inside the tricked-out home of former Ms. California and Oakland Athletic Tarah & Eric Byrnes
15 wood-inspired shower tiles - DigsDigs | Inspo from HGTV Flip or Flop
Rustic Pipe Bathroom Vanity - Iron Industrial light - Pipe Vanity Light - Steel Steam Punk
If rock in the master bath is determined to be cost prohibitive, this tile option would work too.
Slate Mosaic Accent Wall
Rustic bathroom. Wood tile tub, shower surround.
Rustic Master Bathroom - Cool shower head