Just about anybody that makes fiberglass body parts has a line of hood scoops. Harwood, Aero, Unlimited products, US Bodysource. Do a web search for fiberglass scoops. A cheap alternative is an ABS plastic scoop, but I don't know if they can be painted. The kind with the internal bolt flange are nice, and they are easy to install.
I just got a mopar twin inlet scoop for mine. I can't wait to get it on, but I have to make a new base for it first.