Thanks guys. To be honest I was waiting for a flurry of 'oooh you don't want to do that - it is far too dangerous' e.t.c. The reason I want to do this is not to be wizzing down the road at 70mph watching some film.
I love my Lexus and drive it so carefully you wouldn't believe. What I would like to be able to do is to watch / glance at it whilst sitting in traffic. Yes, I know once I completely stop and apply the handbrake I can wait 3-4 seconds and it appears. The problem is that I find it very frustrating willing the traffic to stop when crawling at 2 mph so I can stop and put handbrake on without having to annoy the car behind who sees a gap of 10 car lengths appear before I pull off again. To be honest, I don't think I would look at it in these circumstances any more than I currently look at the screen to fiddle with sound settings e.t.c
Anyway, sounds as though no-one knows how to make the change which sounds like it is a big job.
Thanks for the advice (and any more to come...)
Andy