The first thing I find suspect about this scenario is that you expected to see the flaps move after you'd started taxying. Most airlines SOPs call for the flaps to be deployed before you start taxying, hence if you were looking for a change in the wing after you'd started taxying you wouldn't get one.The second thing I find suspect is that you took off. Most Boeings have a Config warning which would automatically have alerted the crew to the lack of flaps. The third thing which is suspect is that you are still here to ask the question. I don't fly the 767 but I'd be extremely surprised if a heavy 767 could get airborne without any flaps at all.
I suspect the most likely scenario here is that the flaps were deployed but maybe missed seeing them run.