I was thinking about making a kind of "AEG pancho" from a camo pancho and camo duct tape to match my uniform.....but if my aeg isn't going to have any issues I might skip the whole idea after all....
We've all considered that at some point. Let me tell you from experience that covering your AEG will only serve to keep water in, and prevent drying.
A good thing to have for stuff like this is an air compressor. You can blow out the nooks and crannies of your AEG to get it dry, and also get rid of that coat of dust! A PC duster might work as well, although it's not as powerful.
I though this thread would die, but it just won't stop raining here in AZ! It looks like this is an issue we must all address.