Hey, I ride around all year here in Stockholm. My winter ride is a Surly Steamroller fixed, with studded tyres, Nokian of course. I think you will love it, the Surly performs wounderfully with 28+ tyres. I have a friend riding a 1x1 and as well loves it, pm when u get here.
Stockholm is a very friendly to cyclist, loads of cycling lanes and tons of people cycle.