Wow....simple, yet effective. I cant believe i didn't even think of that.
I dont think i have ever seen anyone use sonotube for ports that i can remember. Assuming I'm not the first, but also assuming it isnt very common either. Just not sure if its because flared ports arent an option with sonotube, or if it just simply doesnt work very well.
I had originally wanted to use 8" pvc, but i couldnt find any places that sold it in small amounts. I suggested i might buy a full length of it to my wife and she nearly stabbed me with the spatula she was holding when she heard the price. So i guess using anything other than sonotube is pretty much out of the question for me. hehe

Thanks for the info Yuli