Glad I found this thread and glad to see there is some momentum here. I was looking for this information as the PS4 Warframe clan dojo has banners in it by default, and in a video I was watching on dojo design, their banners had there clan logo on them. Also, the clan emblem was put on every warframe's shoulders like a patch. The clan was NOG (Night Owl Gaming) and their logo lends itself to things like stickers, banners, patches, etc. because it's fairly simple and round.
I actually have a design background too (lol) and the one thing I remember my design/art profs telling us was 'simplicity is the essence of design'. And it had to work at a 1/2" for business correspondence, etc., and it had to work in black and white. From what I've seen in this thread so far, the one that seems to fit the bill most closely is the one Black Death uses for letter head (the green and blue one with the 30 in the middle). I actually think it's pretty clever as well as simple, but I'd be interested in what some folks come up with.
I'm not looking to step in the design arena, but I'd like to know what the official clan colors are (I suggest picking a Pantone version of that green and blue if that's what you like, as Pantone makes the color consistent no matter where it's displayed). That way I can apply that color scheme to the inside of the dojo, but that can be done later, no rush.
Glad to see some real designers involved, I'll be watching to see how this develops.