Try Google+ interface theme for Gmail
Okay, it’s not exactly the “Google Plus” theme for Gmail, but it’s the new look interface Google is planning to roll out across all its products.
You can have a sneak-peek at the upcoming Gmail theme right now. Login to your Gmail account and click on the cog icon on the top right corner. Click on Mail Settings and goto the Themes tab.
Towards the end of the themes list, you can see two new items “Preview” and “Preview (Dense)”. The difference between these two themes is that the “Dense” one shows up more results (thinner) in the inbox.
