Unfortunately, I know what you mean about the bank balance!
I also have some virgin depron. The two sheets I have look about the same size as Half of the one you got, like yours was split down the middle... Anyway, I have been thinking of building a wing with mine. The reason I bought the sheets I have is to make a wing similar to the one in the video below. I even think that his wing uses a motor of the same specs as the ones you've got!
Since you fly heli's, your TX should support elevon mixing, so maybe a wing is a good choice - just sayin'