I think that for a next generation sleeper service, the idea of airline first class beds/pods is a great idea, with A380 style suits for first class (and at a premium).
Coupled with good advertising, to really emphasise the fact that the price isn't just a train ticket but a hotel too - and you don't need to fly late at night then check-in for an early start, or travel stupidly early and arrive knackered, and sleepers should have a strong future given the increasing cost of fuel and other associated costs (e.g. road tolls).
We can't keep running ancient trains forever and let them fall to pieces. We need to look to expand them, and especially look to how we can use them to get Brits into key locations in Europe to give even less reason to fly.
The next time I have a press event in mainland Europe that starts around 0930-1030 and I have to be awake at 3 or 4am to get to an airport, I'll be wondering why I couldn't get on a train at 11pm, relax with a drink, take it easy, sleep and be totally refreshed and ready for 0800-0900.