everything i've read suggests that corn prices will fall, eventually. it just takes some time as the market adjusts to the "shortage". but as more american farmers get into the game. well, even if it can be done and the gains aren't that high, for me its not worth it. unless gas goes up to $4 a gallon that is.
And there you have the real issue that would make people start looking for conversion kits...it would pay for itself over time and with the government rebates available...you'd be ahead in no time.