I am surprised no one mentioned the Caterham blend. Look it up. It's a mix of Mobil 1 0W40 and Toyota 0W20 oil, resulting in 30-grade oil with a very high viscosity index. If you want something off the shelf, then Mobil 1 0W30 is an obvious choice, the only 0W30 oil I have seen on shelves besides German Castrol (a relatively thick 0W30 oil, which you didn't want).