I've just seen this on facebook. It's only in the Express at the moment.
www.express.co.uk/news/health/442876/Cause-of-cot-death-found
It sounds promising/convincing - they have found very strong links with a particular brainstem abnormality, which can then be tested for (and they say treated). It really sounds like they have taken the variables out this time and really hit on something.
Article is very recent so perhaps more will come out over the next few hours/days.