We've been sitting on this one for a few days now to let people have their fun before we draw a little too much attention to it, but there's a rather interesting bug in the patch 3.2.2 client: you can glitch out the model being loaded for your character upon login, and switch it with that of another character. We don't know how long it's been around or how long it will stay, but watch the video above (which is pretty large, our apologies) for a demonstration.
The WoW.com staff has confirmed it works, though the timing required is very precise. You need to be quick, but being too fast hitting one or the other is just as bad as being too slow. A few of us found that we had to slow down our fingers to do it properly, because "fast" to a hardcore FPS gamer is very different than "fast" to a casual MMO gamer. Click first, hit enter second. Not the other way around.
Whether this falls into exploit territory or not, we don't really know. What we do know is that the model 'swap' is only visible for you on your client, nobody else sees it, so nobody else should be impacted by it. It's also only graphical, no benefits carry over from one character to the next. You might see your epic iLevel 258 shield on your level 1 rogue, but you won't have the stats. You can't be a Horde draenei to anybody but yourself, so no screwing with people in battlegrounds. You can't be a unique snowflake like an undead paladin to anybody but yourself.
It's a whole lot of fun to see what a draenei rogue would look like, or a gnome druid. Check out the gallery below to see what came out of WoW.com's experimentation, and a few from our friends, too.