Hokays. I solved this. It appears that they removed Bing from the default_partner_content.json file between 26.0.1656.24 and 26.0.1656.32

here is an older version of that file, pulled from my 26.0.1656.24 files. Replace the file in the Opera\26.0.1656.32\resources\ folder, and voila, problem solved! If you still have the 26.0.1656.24 folder in your Opera installation, you can just copy that one. Download mine if your folder already got removed.