The photos on B&H certainly make it look like the black lens comes with the 5N, but I'm certain I read somewhere it only came with the NEX-7. If they do come with the exact same lens then the price difference between them is strange.
I'm sure that Sony don't view it as either "unfair" or "strange",...it's just marketing strategy which is about gettign as much for a product as possible. Consumer product makers like sony look at the overall mindset of people who buy particular products. Anyone who buys a NEX 7 is a 'bigger spender' than one who buys a less costly product so the thinking is that they can pay more for the lens. Also sony is probably looking at the overall 'package' of NEX 7 plus zoom, and where it 'scores' against the opposition by offering a greater spec. As we know, the price will no fall away as other makers launch ever stronger competition with their own models.