The PQ25 platform that underpins the Audi A1 and Volkswagen Polo is being re-engineered to accept all-wheel-drive powertrains, according to Autocar. That could eventually spell a true quattro-powered Audi S1, as well as Volkswagen's own all-wheel-drive variant, the Polo R.
Whether such a car would ever make it to the U.S. is another question. The Audi A1 itself isn't scheduled for American sale until its second generation, around 2015 (TK), and though the Polo has been tipped for U.S. sale, both the S1 and the Polo R are likely to stretch beyond the American wallet's ability spend on a small car.
Spreading the platform across those two models, plus a likely non-U.S. CrossPolo, could make the business case for reasonably affordable versions of each, however. Whichever way the wind blows on that matter, it'll likely be years before the re-engineered platform finds its way under a production car.