I'd like to say if you report something once, it may be a fluke. If you report twice, then there may be something to it. But reporting something three times, well - to me, it is here to stay (at least for a while. This is the third time I am reporting a thread on folks spotting Google Checkout icons on Google AdSense ads.
I have still not seen them myself live on a Google AdSense site but it appears more and more people are noticing it on a daily basis.
Google Checkout icons can be seen on several AdWords ads on the top and right side of a search on sporting goods.
Scratch that, I have seen a Google Checkout icon on topix's sporting goods section. Scroll down a bit, and you may see an ad for "Dicks Sporting Goods." They accept Google Checkout and thus have the Google Checkout icon on the AdSense ad.
I think this just may stick for the near future.
Forum discussion at DigitalPoint Forums.

Comments:
Richard
02/13/2007 11:27 pm
I have a screen shot of Google using a Large Checkout Graphic. Who should I email it to?
Barry Schwartz
02/13/2007 11:29 pm
Don't, Google Checkout blog announced it <a href="http://googlecheckout.blogspot.com/2007/02/shopping-cart-badge-updates.html">here</a>, I see them also.
Richard
02/13/2007 11:29 pm
http://www.google.com/search?q=cisco%20learning%20network&sourceid=groowe&ie=utf-8&oe=utf-8 Here is the link to see Google's Large Check Out Button