I watched A Single Man twice, and I have fallen in love with the white angora sweater Nicholas wears throughout the film. I have been trying to find something similar and have been browsing through eBay and websites selling angora and mohair. But no such luck. It seems Nicholas's sweater was custom-made by a weaver in England. This is what Nicholas said about it in a recent interview:
"Oh the angora sweater? Yes, it definitely had a life of its own. It got a lot more attention than me, most of the time, whereby it would frizz up under the hot lights and need to be hair-sprayed down, because it would get too fluffy. It needed a lot of attention. I’ve become quite intimate with that sweater."