How many categories do you have for each custom stylesheet? And how many different category specific stylesheets do you anticipate needing?

I suppose it would be possible to "trick" ZC into loading the same css file for multiple categories by using a bit of php to call for the same category specific stylesheet. Something like (in pseudo-code)...

if I'm in category 1,2,3,4,5 or 6
then use stylesheet c_1.css
else if I'm in category 7,8,9,10
then use stylesheet c_2.css
end if

But that seems a lot of work for something so simple. If you have, say, 10 categories that each use one stylesheet, and 10 others that each use a different stylesheet, then you simply create those 2 stylesheets and make 9 copies of each of them, each with its appropriate name. After all, you're not duplicating everything that is in the main stylesheet.css file. You're just putting styles in the category specific stylesheets which need to be different for those categories. So having a bunch of copies of these relatively small files around doesn't slow things down or hog resources.

Rob