The ones 
Mamu suggested are particularily nice because the plastic case is just the right size to hold 3 atomizers for traveling.  After cleaning, I line mine up in these cases to keep the in use atomizer neatly stored.  A silica packet will also fit on top inside the case.
 
The Pit'r Pat cat treat/dog treat metal cases are nice too.  They hold about 5 atomizers nicely.
 
For all your SD needs, you would find a lot of answers at Trog's forum.  There's a list of suggested/recommended items.  
ecigscrewdriver.com just click on forum and register.