As for booming, i don't see it. I've only met one other person doing the veggie oil thing, he's my landlord and he lives a few hundred miles away. The competition for used oil here is not much of a competition at all. As for shady, its not as much fun if everything is on the up and up right? My trunk does however resemble a home-made bomb.
I have two places I collect from on a regular basis, I have a couple of here and there hook-ups as well. One of the places I go I actually go in to the place and filter on site, which is alot easer , I just have to clean there fryers. So its win for both of us. As for eating the type of food that comes from this oil, not so much.
Like chicken wings and french fries,a hint of methol cigarettes. It'll smell(feel) alot better when i get the two or three hundred gallons of unfiltered I have piled up ran through this ugly contraption.