You can presently in classifieds define up to 6 extra fields to ask different questions. You can upload up to 6 images per ad to respresent the ad. Classifieds is not a forum so if you want a forum you need to get one first that we integrate with and then install classifieds to integrate with the forum.
You can view here different sites running classifieds but can not be sure of any running them for rentals
http://www.photopost.com/action/index.php