What about brands that are known to exist in-universe but don't have any official cars in-game yet, like Soliad and Charmand? Occasionally someone does release a mod under one of those brands.
Don't think it has a Y in it. Also, it could be useful to have a "BTO" (for "badges taped over") tag, to indicate when a mod car is really a real-life model but released under a fake (official or otherwise) brand i.e. Hirochi Prasu. Or would that also attract the wrath of the Copyright Monster?