My old time buddy, Darrin Ward (founder of SEOChat back in the day), blogged about noticing Sitelinks in the Google AdWords ads. Here is a picture, which I can see myself, for a search on staples.com.
Notice the four links directly under the ad, those are commonly known as Sitelinks in the Google organic search world. They kind of look like the one line product links but these are category specific.
I am pretty sure I saw a form of this a long time ago, but I cannot find my blog post on that find.
In any event, it seems like Sitelinks are here for Google AdWords ads.
Forum discussion at Search Engine Roundtable Forums.
Update: Here is the official Google statement on this test:
As part of our ongoing commitment to help users find the information they're looking for online, we are testing a feature in which links to various pages of an advertiser’s website may appear within the text ads on Google.com. Presenting multiple landing page options is intended to make specific website information such as gift registries, special deals, store locators and the like more easily accessible to users. It also offers brand marketers a new way to quickly engage potential customers. This feature is currently in a limited beta with a small number of advertisers.