I love this idea! Heather over at the Coterie posted about a great moving announcement. Depending on how much you wanted to spend, you could use big boxes, bubble wrap, etc.
Years ago, I found a very clever moving announcement in a design book. It was done by a graphic artist and featured a picture of an alligator superimposed with the words "see you later alligator", a popsickle superimposed with the words "let's blow this popsickle stand" and a baby superimposed with the words "hasta la vista, baby."
I'm so glad there are people out there who are so creative! Thank you, Matt!