Admittedly I've not read the books so I can't talk with any great authority on the subject, but still - I think Young Bond movies as a concept is something that could work very well.
Think about it: The Harry Potter, Twilight, Percy Jackson films have all been great successes and they are of course based on young adult books. There is a market for that sort of thing obviously and with the main Bond movie series becoming more adult and realistic there is a danger that the family audience they used to go for is being left behind a tad.
The idea is quite simple. The Charlie Higson books seem to receive great acclaim and have a loyal following of young fans. They are officially endorsed by the Ian Fleming estate, so I really do think it would be prudent of the Barbara Broccoli and Michael G.Wilson to strike while the iron is hot. They could set up a brand new series of films to exist alongside the current ones.
Obviously, the current ones will be the main priority for the duo since they are producers. The way they'll need to do it is to be "Executive Producers" on the Young Bond series and hire a new producer whom they trust to oversee the series. This role could make a star of a talented young newcomer. They could aim for a straight PG rating and guarantee you they'll have the audience sewn up.
Like the main series they could have title songs, but for these ones get stars who appeal to younger audiences. Artists like Katie Perry, Jessie J, Lady GaGa?
The mission statement for Casino Royale was to start afresh taking the character back to basics and seeing how he became the man we all know and love. With a series of movies chronicling his formative years - they could go one better.
Also (and this is a bit of a wild one) they could take a leaf out of Smallville's book. That show acknowledged the characters history with guest appearances by actors steeped in Superman lore. Over it's ten years it had brief turns by Margot Kidder, Marc McClure, Helen Slater, Terence Stamp (who appeared in a semi regular role providing his voice), Dean Cain, Teri Hatcher... and of course the man himself Christopher Reeve.
Perhaps Young Bond could try something like that? A few older actors who've previously played love interests and sidekicks could show up as teachers, different relatives? Maybe someone like Roger Moore, Timothy Dalton, even Pierce Brosnan, maybe even George Lazenby could show up in a flashback as an Uncle or Grandparent or something? Give Jason Connery a nice juicy role? (Sean Connery's retired of course but even if he wasn't I doubt he'd touch it with a barge pole, lol)
I'm sure many will disagree but I think it would be an absolutely wonderful idea.