I think one problem with the Zed is the exhaust hangs quite low, it's usually the Y and mid pipe that scrape speed bumps first, so in order to fit a flat bottom, brackets would need made for it to hang low enough to clear it and with it being made possibly from plastic, would need to clear it enough to prevent it melting, which in turn lowers the ground clearance by quite a lot. In a lot of cars that come from the factory with flat bottoms they have cut outs for low sections of the exhaust to fit through and that complicates the whole project.
Hopefully I'm exaggerating as I'd love this to happen, especially if you plan to make more than 1
Abbey might be able to help, they have something similar on their 350 drag car.