I am wondering if you could put up some kind of greenhouse framing, where you could install side curtains that could be closed down during the cooler part of the year.  When the corn gets some size to it, and the weather warms up, you could roll up the side curtains.  ????  I dunno...... just a thought that crossed my mind.

I've seen guys transplant sweet corn.  I don't think that gain a lot of advantage, maybe a week ?
  Maybe that's enough to make a difference?

I've also seed guys seed sweet corn under plastic.  When it warms up, they remove the plastic.   Right now, I know one local grower still have row covers over his sweet corn.  Depending on how windy it is in your area, that may or may not work.