Rob's absolutely right. A lot of "players" use a couple of WSMs or other combinations of cookers. Tim and I have been competing with a Bandera and a WSM - last time out a Bandera and two WSMs.
Lot's of homemade rigs, lots of "bachyard" horizontals, etc., etc. Do not let the lack of a big cooker keep you from giving it a try. In my earlier post I was indicating what will happen if you get hooked! :D You don't need all that to compete.
The backyard division has a lot less pressure but a lot of these guys do backyard for years - maybe the one local event but they do it every year! One huge advantage to doing backyard it that the meats (usually chicken and ribs) don't take all night - you can setup Friday, visit, etc. get some sleep, fire up the cookers at 6 am and make the 12:00 and 12:30 turn in's with no problem! :D
Southern Brethren BBQ Competition Team
"It's all about getting paid!" - Myron Mixon
"I love being hated in my hometown!" - David Hair
KingFisher Gator Rotisserie cooker, WSM, Stainless 5 burner with IR gas grill, Turkey Fryer, Weber JD Commemorative grill, slightly used Bandera chamber for future use as a cold smoker, Masterbuilt 40" insulated ELECTRIC smoker