I would LOVE to see a movie of it. Honestly, I don't care whether the cast is good or not-- I loved the "Sweeney Todd" with Johnny Depp even though almost no one could sing. I feel a movie's more about the visual experience, and a play's more about the audio experience. Still, I think they should have a lot of "musical theatre" performers and a FEW celebrities playing roles-- for example, a celebrity should NEVER play Enjolras because that's a really vocally demanding part (unless he's a celebrity who happens to be an impossibly good singer, too) but Marius could probably be a celebrity. Thenardier could be a celebrity, too.
The thing is, I would just love to see the musical transferred to real sets. To have people actually joining up and marching down the streets in "One Day More," or to actually have a real barricade scene, or to see Javert's Suicide... That's why I feel like a movie would be such an amazing thing. With "Sweeney Todd," there was never much emphasis on the different sets-- Sweeney was usually in his barbershop, Lovett in her bakery, and so on-- but Les Misérables is a show with so many sets, and I think it would look amazing and stunning on film.
If they make a Les Misérables musical film, though, they should have some of the original leads in cameo roles-- Colm Wilkinson as the Bishop, or Michael Ball as the "You at the barricades listen to this!" guy, etc. I think that would be awesome.
I am playing the Queen of France right now in a play. Try not to decapitate me.