There's a stretchx and stretchy variable; it stretches the image like the zoom variable does, but only on one axis.
I'm not sure, but I don't see why you wouldn't be able to stretch an image and then rotate it. You could make, for example, a lightning effect this way. Stretch the lightning image to be the distance from one player to the other, then rotate it so that it goes in the direction of the other player.
I've used stretchx and stretchy to make some nice effects.
