Hey Dave,
We have two that run out of this very site. Kato's (out of Fla.) which was concluded just recently and The Hot Pepper Awrds which are just underway (if you are a commercial sauce company or work out of a commercial kitchen). There is a contest called "Open Fields" which runs out of Indiana or Illinois (try to google it). Depending on your location, there is also a monsterous contest in Austin, Tx every year, but you must deliver your sauce personally, which can be tough.
Good Luck!