I have not heard of using cornflour as an egg substitute, but I have heard of cornstarch and water as an egg substitute. Here is a website that describes the many different ways to substitute for eggs:
I have also made an omelette using chickpea (besan) flour and water and added spices and vegetables into it. Chickpea flour has a savory, eggy taste to it. Tofu with turmeric and other spices scrambled makes a nice egg substitute also.
In the UK and Ireland corn starch is sold as cornflour, what Americans think of cornflour then is probably polenta or hasina mesa (don't think I spelt that right!). But yeah I have heard of cornflour being used as an egg substitute, both dry and disolved in water but I've never used it myself.