The forums are buzzing about a new Google AdSense format seen around the Web that has both an image ad and text ads in one ad unit. JenSense has a picture of it in action and you can see an other screen capture of it in action here. One forum member said;
Tonight I noticed on my blog that my 160x600 ad had a picture of a basketball in the top spot.
Others report seeing the image ad in a 120x240 AdSense unit.
This is definitely feasible, since Google has recently been reported mixing Link Units Within Standard Ad Units.