After seeing the link on the discussion board showing photos of freezing bubbles, I decided to see if I could do it. It was still sunny and not quite cold enough but the bubbles did start to freeze. The best one, which I caught on the wand, imploded before I could get a picture but it had lovely frost forming. I thought I would post these anyway and, if you look closely, the top middle and right and bottom left show signs of freezing.
I used Karo syrup, dish soap and water without measuring, but probably used too much water. Good luck!