Jacques Duflos offers an Auto Custom Shape Addon for Blender that will save some time when creating Bone Custom Shapes in Blender. Check out the page for Auto Custom Shape Addon for Blender for Creating Bone Custom Shapes here.
Jacques Duflos notes: “This script is meant to save some time and to facilitate the design of bones custom shapes. You can activate this script via File ? User Preferences ? Add-Ons ? Rigging. Once activated, a panel will appear at the bottom of the bone properties panel with a single button. You can as well use the search menu (space bar) and look for Add custom shape. This script will only work if in pose mode or edit mode, because you need to select one single bone. If you didn’t select any bone or if you select multiple bones, a warning message will be displayed in the main menu bar. If everything goes ok, an Info message will be displayed.”