Tested & confirmed on 3.3.5 Trinity/mangos.
Really simple bug:
Pursuit of Justice - Spell - World of Warcraft stacks with Crusader Aura - Spell - World of Warcraft combined with Aura Mastery - Spell - World of Warcraft.
How to do it.
Mount up, put on any aura but Crusaders Aura, turn on Aura Mastery and pop on Crusaders aura which now applies 40%+ speed, once Aura Mastery has worn off the aura stays until you change auras.
Combine with any 310% mount for really quick travel and a 155% land mount.
Obviously this is bannable and there is no way to hide it, so use with your own risk.