You're misunderstanding me. Using the VW Golf as an example, say you bought a 1.2 TSI: the basic car would literally only have the bare minimum to pass type approval/legislation, so you'd have all the airbags, the ABS, the thiefproof locks, and the immobiliser as standard, everything else would be optional: alloys, central/remote locking, aircon, electric windows etc, even upto the power steering. Essentially, what I mean is that a Golf 1.2 TSI would just be a Golf 1.2 TSI: there wouldn't be the S, SE, SE-L models, or option packs, you literally just pay for the things you want.
Given the current craze of manufacturers trying to sniff out every conceivable niche, I'm surprised no one has thought of offering that: potentially, it could be a great success!