I've had measurable success with simply copy and pasting the chrome-extension_<extID>_0.localstorage
and chrome-extension_<extID>_0.localstorage-journal
files found at
Windows NT5: %userProfile%\Local Settings\Application Data\Google\Chrome\User Data\Default\Local Storage\ Windows NT6: %localAppData%\Google\Chrome\User Data\Default\Local Storage\ OS X: ~/Library/Application Support/Google/Chrome/Default/Local Storage/ Ubuntu: ~/.config/google-chrome/Default/Local Storage/
from system to system, but, as it depends how the developer has chosen to store the configuration, it doesn't work 100% of the time.