Just paint the grille black. Heck, '70 grilles are pretty darn subtle anyways so if you want that look, blacking out a '73 grille pretty much does the same thing.
I concur, round taillights are cool, especially if you replace the backup lenses with the running taillights. Also, hi-tech has LEDs for the round taillights. How cool is that?
I'm however not a fan of the side marker lights; I would just shave those completely for a smooth look.