I really hope that Destiny has something like the clan dojo in the release. A massive enclosed instance where you can design, build and decorate to hearts content and then invite other people to your clan dojo so that they can trade items with you (I don't mean that I want to trade items in destiny, just for people outside clan to visit). For one thing in warframe you can build a dualing room and obstacle course in the dojos. So for people wanting to have private matches how about the concept that each clan can build their own "training grounds" and invite rival clans that way? Could setup unofficial leagues that way by playing home and away matches.