My experience growing up on a vegetable farm in Western New York has taught me that earlier sweet corn production can be achieved by using a clear plastic mulch. The planting date can be 7 to 10 days earlier than the normal planting date for your area.
The first step is to plant the corn into rows thirty inches apart with eight to ten inches between seeds. Next, you simply roll some clear plastic mulch (available at most garden centers) over the top of the seedbed, and bury the edges in small furrows. Make sure there are small holes in the plastic to allow the soil and plants to breath. The clear mulch acts as a miniature greenhouse, keeping heat and moisture in the ground. The corn will come up and should be allowed to grow under the plastic until it is several inches (approximately 6 to 8) high. Then the plastic can be sliced down the middle and carefully removed. Use of an early variety also aids in early production.
There is a little risk associated with growing corn under plastic. There is an increased risk of seed deterioration in the soil, especially if there is cool and cloudy wet weather. Believe it or not, I have seen newly planted plastic sweet corn fields covered by several inches of snow, and have enjoyed the corn produced there several weeks later. With some luck, you too can have the earliest sweet corn around!