The proper responses to…
The proper responses to silly length requirements are two:
Using an attractive typeface instead of ugly Times: Palatino Linotype, Book Antiqua, and Georgia, for example, all chew up a good couple pages more than Times New Roman in an essay of a few thousand words. And they make it look nicer.
Footnotes. Lots and lots of glorious footnotes, ferreting out every corner of every digression along the way that doesn’t belong in the main flow of the essay.
I’ve never had much of a problem on this end: I’m naturally long-winded, and like to fill out my essays with silly flourishes, so my essays usually clock in well over the length requirements. But having to learn how to shorten essays, from time to time, has helped me discover a few of these tricks in reverse.