=p, There is No cinematic MC model. There is special ingame lighting for cinematics but the models are the same and are not actually high resoultion or high poly.
The cinematics use the exact same shaders as normal playing models. The special lighting just for cinematics really brings everything out a little bit more to make it look cleaner and more realistic in a way.
There is no special MC model in Halo 1 or 2. There is only one, no High Poly or Low Poly.
ive always wanted to watch the cinimatics in HD. my GF's parents just bought a HDTV i think 1080p tho im not really sure. but i watched the preview that was on MNF. i was crying(not really) it was so amazing.