Yeah, that's one of the main reasons I purchased a larger smoker. Once I had the water pan on my old one, there wasn't enough room in the cook chamber without being creative. The smoker I have now works well for getting everything on that I need for most any competition. My goal is to scale up to catering for about 150 people and continue to scale until I can open a BBQ joint of my own. I'll take it one day at a time.
There are places that rent smokers if you need to. I'm not sure if they are available where you are but it may be worthwhile until you can make the jump to the next size up.
-Cyber