I've posted an alternate idea for handling large drop down lists at:

http://www.gossamer-threads.com/...um9/HTML/000080.html

Please follow up on that idea there.

As for Alternate Categories vs Multiple Categories, the only difference you seem to mention is in how the category lists are displayed, and on finding an easy way to enter the information.

I prefer a link belonging to a main category, as it makes it easy to determine what category a link should come up in when searching. I don't think you should get the same link twice do you?

Cheers,

Alex