1. Search categories can have sub categories You can search keywords but will need minor tweaks to add categories.
2. Support two drop down lists next to each other listing different things Yes, you can have multiple types of lists in eZ (known as datatypes)
3. Visitors can register/login to add content within a category? Other visitors can register/login to leave comments and rate the content Comments yes, rating out of the box no. You can use a plugin http://ez.no/developer/contribs/applications/star_rating
4. Registered visitors can also upload articles and documents You can upload documents or have them converted to an eZ Article. I would check permissions and Virus scan here etc.
Hope this helps.
Tony
Tony Wood : twitter.com/tonywood
Vision with Technology
Experts in eZ Publish consulting & development
