denisl - 11:32 am on Sep 10, 2013 (gmt 0)
I was in the same situation as you, when reading the bit of the adsense TOS about not having other ads that look the same as google, I was only thinking of text ads.
Then one day I saw that on one of my pages which had an affiliate ad and adsense, both had the exact same image. The only difference being the little blue thing in the corner of adsense.
I went to text only for most of my adsense ads after that. I also raised the question here about a year ago and the consensus was that you should avoid this happening - not worth the risk.