Actually, I believe Sony a while back showed that at high bitrates, MPEG2 and H.264 were indistinguishable, so I can imagine them considering mpeg-2 instead as it is much nicer for editting.
RAW is unworkable unless you can figure out a good way to compress it. RED uses a wavelet compression scheme, and I have no clue how good it is or if it's worth the time, and I doubt they'd license it to Canon. The last thing we need is a format that canon invents to support 'raw video', which isn't supported by ANYTHING other than canon tools.
As I mentioned in another thread, Apple ProRes would make an AWESOME addition though. It definitely requires a much higher bitrate than H.264, but still within the means of fast compact flash cards. It can also record in 4:4:4, and would require no transcoding when editting (final cut and avid support it.. don't think premiere does though).