17 years ago, CGI dinosaurs in "Jurassic Park" essentially put hundreds (if not thousands) of Practical FX technicians out of work - or at least got the ball rolling.
Apparently, Warner Bros. "Green Lantern" movie is looking to do the same thing to the costume design business. So says Slashfilm: http://www.slashfilm.com/2010/04/11/exclusive-green-lanterns-suit-will-be-almost-entirely-cg/
Short version: Ryan Reynolds is doing the part wearing a motion-capture suit over most of his body, and they'll be rendering a CGI Green Lantern costume over him in post-production. Which, of course, makes perfect sense because there's simply no way that GL's ridiculously complicated uniform of a black-and-green body-stocking could possibly be accomplished with fabric. Clearly, this was a job for a few million in rendering tech. Left unsaid is whether or not Reynolds "actual" head and face will be visible, or if they're going to roll the dice and see if human fleshtones can look as "acceptable" as Na'Vi ones.
Something like this has been coming for awhile. Warners has been making chirps about doing the next Superman with a "real" Clark but a "CGI Supes," and this certainly sounds like what they might've been talking about. Done right, this could theoretically end the problem of actors having the personality but not being in the right "shape" for roles like this... though I'm already filled with nightmare visions of the disembodied heads of gangly character actors and/or over the hill "stars" pasted on top of brawny comic-appropriate CG bodies.
It could go VERY wrong - it reminds me of the Holophoner Opera in "Futurama" which, for some reason, required live actors "wearing" hologram costumes - but I could easily see something like this become a cost-saving standard and a way to "broaden the field" of available actors. Reynolds, for example, has generally been in great shape since Blade 3; but concievably an actor with just an average (or "too old") build could play Superman, Flash, whatever this way. It might also solve the problem of actors not being able to MOVE inside Batman's cumbersome, impractical costume.
Or it could look incredibly silly.