It was reported in early November that Google was trying a new feature out within their AdWords listings, for Google Checkout merchants. The old reports said there was a link with a plus sign that read "Products from this Advertiser."
The new reports are similar, but the text for the link read "Show Product Results For." The link was found directly under a Google AdWords ad for a search on skull luggage, but I am personally not able to reproduce it.
The member said it appears to a test limited to larger advertisers, such as luggage.com and target.com. But I have a feeling it is a limited test with some Google Checkout merchants.
Forum discussion at WebmasterWorld.