Numerous single core phones run ICS without any problems, I'm a bit confused about you mentioning worrying about the Xperia because of its having a single core, the HTC One V is also a single core device. While the ability to run ICS on a single core isn't an issue, if you can get a multi core device in your price range that's available on your carrier I would definitely recommend it, doesn't help to future proof a bit especially when purchasing a new phone. Good luck.