KaW merchandise is pretty self-explanitory. I think the idea of T shirts saying things like "i'm addicted to KaW" or "KaW for the win!" Or something like that. You could throw some pictures on there too. You could sell T-shirts, mugs, blankets, ipone/pod/pad cases, pillows, cups, heck, you could sell plushies for the kids. (Note:Some parts are not well though through)
id buy some of it this game has already taken my outside of KAW social life may as express it for all to see!!
If they throw some merch in for real money spent on nobs and xtals as well as offering it up outright it's a great marketing tool, great reward, and additional revenue stream for ATA. I'd rock a Moutos the Malevolent shirt when I'm out and about.