I think it was Direct Line that were doing a policy for named drivers that would increase NCB's, but, it is a very risky business. Every time I've been stopped (last time I had already stopped, it was in sainsbury's car park while buying fags) the first thing they ask is if the car is insured in your name.
If it gets to the police, or insurance company that you aren't just a named driver, but the main driver, your insurance will be invalid and the popo will try and bum you!
I'm over 30 now, and still have my mother as a named driver, drops the premium on mine considerably still.