Last year we planted 8 blocks of corn (3 different varieties). As corn is wind pollinated you need to make sure there are sufficient plants to obtain a good pollination rate. We stager our plants so that we have a continuous supply of corn for the market throughout the summer, which also stagers our pollination periods so there is no cross pollination. Look at your seed packets and see what the time to pollination and time to harvest is and you can stager your plantings so that different varieties are not pollinating simultaneously. A good standard rule of thumb is that a block of corn should not have less than 4 rows in it to obtain sufficient pollination. Each of our blocks is no less than 4 rows that are each 50ft.
Corn for privacy sounds like an interesting idea, although it wouldnt be practical for us to use here with production corn on the place. Our plan is to plant a row of sunflowers along the fence in our front yard for privacy.