Random posts within a category?

I’m looking for a plugin which allows me to put a certain number of random posts from a category at the top of a category page. I’ve set my site up so that I’m using Elastic Dog’s “Faking Mulitaple templates” code (http://elasticdog.com/2004/10/faking-multiple-templates/) so I’d like to say, something like:

\if ($cat) {
require_once('includes/random.php');
require('includes/category.php');\

So every category page would have a certain number of random posts from that category at the top.

I’ve looked at the random plugins available (such as Skippy’s, MooKitty’s etc) but they’re no really what I’m looking for. The closest likeness would be random_posts from http://www.w-a-s-a-b-i.com but there’s no function to specify which category those random posts would be from.
Can anyone point me in the right direction?