We removed a wall in our home that used to separate our kitchen and dining rooms. The main entry way to our house is in our kitchen.... with the dividing wall gone your eye is naturally drawn toward the north wall of our dining room. AND IT WAS PLAIN AND BORING.
We needed something worthy of commanding the eye's attention. So to give the room more interest we turned it into the ultimate DIY project: We created a faux stone feature wall. It was fast (done in one week instead of waiting 4-6 weeks for ordered panel); and it was easy (joint compound, masking tape and paint); and it only cost about $70.

Step 1: Mapping

To begin I used masking tape to "map" the placement of stones on the wall. The width of the masking tape is how large your "grout" well will be. I used 3/4" - I needed about 1 1/2 rolls to cover the 127 square feet with large rock.

Step 2: Cover With Compound

Once you've mapped the entire space it's time to cover it with joint compound. I used Dap Lightweight Wallboard Joint Compound. I needed about 4 gallons to cover the 127 square feet of wall space. Slather the compound over the entire space (including the tape). Try to keep the thickness between 1/8" and 1/4" on the wall and be sure to give your rocks form and texture as you go. Once your rocks are filled in remove all the tape (this needs to be done while the compound is still wet): this is the area on the wall that will be recessed from the newly formed rocks and can be painted as grout. The compound will need to dry for about 24 hours.

Step 3: Paint Base Coat

Once the compound has fully dried paint the entire space with a base coat color. This color will be the most prominent in the appearance of the stones.

Step 4: Give Stones Shape

After the base coat of paint has dried create more texture in your rocks by adding shadows and highlights. Place wet base color paint into two different containers. mix black acrylic into one (for shadow) and white acrylic into the other (for highlight).
Start with shadows. Look at your wall and find the areas on each stone that are shallow. Paint those areas with your shadow color by dipping a wadded up plastic bag into your paint and dab it on the wall.
Use the same method for your highlights using the highlight paint color and dab onto the wall in the highest (thickest) places.

Step 5: Grout

Now it's time to fill in the grout well that was created when the masking tape was removed. I used acrylic paint to mix together a dark gunmetal color for the look of our grout. You could also choose to use colors to simulate dirt if you chose.