Every single one of your examples in the first statement is grammatically correct. You can call it ridiculous, if you want, but it doesn't change the fact that

Every single one of your examples in the first statement is grammatically correct. You can call it ridiculous, if you want, but it doesn't change the fact that it's grammatically correct to phrase it with the noun being pluralized. In your other example, it doesn't apply because "Red" comes before the noun and a "Nano" isn't a thing so it's not a noun either. If you want to say "I have two Nanos", then you're using a colloquial description that turns "Nano" into a noun. Mocking rules of grammar doesn't make them incorrect. It is a weird rule, but it is the proper way to write and speak the language.