Hi. I'm a long-time reader, first-time poster.
Anyway, this is isn't an exploit, but a fun little trick nonetheless. By stacking the "Grow" buff (obtained from witchdoctor in the troll village in southern durotar), an elixir of giant growth (http://www.thottbot.com/?i=7015), and the BG Berserking buff, you can get really, really big. Only lasts for a minute of course.
http://i71.photobucket.com/albums/i1...2/realbig1.jpg
Yeah, I had an orb of deception on. Just 'cause Night Elve's are tall. Wanted to maximize the effect.
http://i71.photobucket.com/albums/i1...2/realbig2.jpg
This is a bad pic because my screenshot-unfriendly UI is in the way, but it shows the buffs and stuff.
Easiest way to do it is to go to the witch doctor and have someone queue you for WSG. When it pops (instant on my server, usually), talk to the guy repeatedly until you get the grow buff, then enter the BG, run to the zerking buff, afk out (if ya want), and then pop the elixir of giant growth. Boom, triple big.