Google quietly announced on Google+ a new version of sitelinks named account level sitelinks. What this means is that sitelinks can show with any of the ads in your account automatically.
"Campaigns and ad groups that don't have campaign or ad group-level sitelinks, respectively, will automatically use sitelinks created at the account level," Google said.
Here is a sample:
Here is how they work:
You can add sitelinks at the account, campaign, or ad group level. You specify your link text (what shows to people) and URLs (the page they click to).
In some cases, we might supplement your sitelinks with descriptions that you've provided about those pages. Either you can add those details yourself when creating or editing sitelinks, or we can automatically use information within your account related to individual sitelinks—for example, from various ads in your account. By showing additional information with your sitelinks, your ads can be more relevant to potential customers.
More details can be found in this help document.
Forum discussion at Google+.