Peter Jackson has said in interviews that he's been working on the Blu-ray release. I think we'll see them at some point next year, most likely as a box set with all three films. Hopefully we get the extended cuts in addition to the theatrical cuts and Warner doesn't force us to double dip.

The films weren't shot with HD cams; they were shot on Super35. Film has a higher "resolution" than HD, so that's actually a good thing. I'm very concerned that the recent anti-grain trend will lead to digital noise reduction on these releases, which removes film grain--along with high frequency detail. It's been a problem on many recent Blu-ray releases because of misguided studios trying to make films look "clearer" and more like video.

I doubt they'll have to redo the CG from the ground up. It was most likely rendered at 2K resolution during post production, which is slightly higher than HD's 1920x1080.