You could create a basic kit and provide instructions for adding the details. Built up paint/paper/card stock/balsa/basswood/whatever That way, you sell a high quality kit that can be either no details, low details or high detail, depending on what the builder wants.

Honestly, I think that because there are so few kits for a Nike Herc available (any?) that anything you produce will be a good kit that sells well.

Eh, just my $0.02

-Aaron