Okay, I'll check them out. Thanks for the link. I have a couple local places I might call first to see if the shipping cancels out any savings, however.
Although I'm wondering if I'll even change my setup again. I took the 2' section of vent pipe I bought at Lowes, bent it to roughly the shape of the flap at the end of my chute, and stuck it on. I pinned it in by bending one tiny corner up underneath the large "wingnut" you can't see in the pictures (it's on the other side of the chute for adjusting the flap), and stuck a high-powered magnet on top of the chute for extra support.
It works rather well, only had to adjust it once yesterday in two full loads of chips! I'll put another two truckloads through today and see if it needs augmentation.
Thanks for all the replies, definitely got the mental gears turning!