as for me it is first to have been heard "mind you"
i'm not clear about this question. please tell us one of sentence include "mind you"
if it meaning is "It is when what you are about to say contradict a little what you had said previously' we say "そうだとしても”or”たとえそうであっても""しかしながら”.
but it meaning is "incidently" i haven't idea.
Cigarettes can be bought everywhere in the sreets in the many vending machines,mind you, as from June, it will not be so easy to buy cigarettes from these machines.