gumtree.com.au functionality is more advanced than any classifieds script offered as off the shelf solution. We have basic classifieds website features which can be viewed on our home page.
Youtube video integration is requested before as well and we are working on it.
Regarding rating user, we do not have this feature in classibase. If you want this feature you will have to hire dedicated developer from elance or similar website. Also you can search for scripts with already built in review feature. You may find it for eCommerce or auction scripts working similar to ebay maybe.
I think you want to rate like on ebay after sale, linking to item sold. Well ebay can track if item purchased by user but on classifieds website it cannot be tracked because you do not complete payment on classifieds website. But still this feature can work like a regular review including item title that is sold and review left for.