I have also seen Varroa mites on queens. A few times, but not very often, so I don't believe that queens are more attractive to the mites, than other bees are. But it certainly does happens.
And, when I've ran queen cell builder colonies, without any open brood, for extended periods of time, I've even seen Varroa riding queens as they emerge from their cells. A very unpleasant and disconcerting site.