Since there is no way to do this currently in WordPress without hacking the template-functions-category.php file, I'll go ahead and request it here. I think this would be useful.
It would be great to change the list type used for listing out categories by passing a parameter ('listtype=o', eg) through the wp_list_cats() function.
It would also be nice to pass $before and $after parameters if you're turning lists off so you don't automatically just get a
<br /> tag.
Are other people interested in seeing something like this? Speak up!