I was amazed how easy it is to paint in "faux grain" using this funny little rubber tool.
You just apply the wood stain and then drag the tool along, rocking forward and backward to open and close grain lines. It is amazingly realistic and surprisingly easy.
It is called a "ZAR Graining Tool".
The same tool will make vein grain (close straight lines), heart grain (opening and closing of grain ovals) or quarter sawn grain (widely separated straight lines). Available in hardware stores everywhere.