This question about zip bombs naturally led me to the Wikipedia page on the topic. The article mentions an example of a 45.1 kb zip file that decompresses to 1.3 exabytes.>
Perhaps, on unix, you could pipe a certain amount of zeros directly into a zip program or something? Don't know enough about unix to explain how you would do that though. Other than that you would need a source of zeros, and pipe them into a zipper that read from stdin or something...