Well it can never be 4:4:4 ; so how is the colour resolution calculated?

since the resolution of a video signal is always calculated from the luminance, you could say it is the resolution from the CCD.
if it is a DV camera, anyway the signal is downsampled to 4:2:0 (pal) or 4:1:1 (ntsc).
Then you can expect the guys are wise enough to build a bayer that reflect this compression.
currently a bayer filter can be RGB or YUV, the YUV being closed to DV standard. RGB bayer require to create the picture into a memory and then convert back to YUV.
A YUV bayer is not made of RGB cells but Yellow, magenta, green (if i remmeber correctly).

Here is a link to a Steve Mullen article.

http://images.videosystems.com/files/127/305vssexpertise.pdf

If you google his name or seach these very forums with combo's of his name and key-words you will get lots of great info.