It seems that Google Experimental Search has lost another one! The following was removed today:

"Keyword suggestions

Try different keywords to improve your search results. As you type your search, Google's technology provides alternative suggestions to your queries in real time. This feature is also available on Google Labs as Google Suggest.

Try out this query: google"

google.com/experimental/

It's no longer an experiment since it has been enabled by default at google.com.