I think the question comes down to price and how custom it will be, if its just a tank then the cheap china stuff is fine, but if your going to make something that can be installed into an unused section of the engine bay, or something like the RIPS R33 one that combines the catch can, washer bottle and overflow bottle then you might get some interest, a bit of research of whats available, which ones people want and how much cheaper you can do it for would be a good place to start, once you have something maybe try a group buy and get an order for 5-10 at a time.