I remember a machinima called "The one left behind" or something very similar. What it was about was that there was a soldier who wasn't trusted by anybody except for one person. He was sent out on a mission, and got captured. Ended up fighting his way through hell and back to get back to sandtrap, only to realize that they all had abandoned him. After the epic climax at sandtrap, he was injured badly, but noticed that if he could get back to the banshee that he stole, he could get back to the fleet. He started crawling all the way across sandtrap to get there, but then the banshee was destroyed.
It was a sad story, but the reason why I told everybody about it straight up was because I believe that the people who made it removed the videos. It was a first person machinima, I found arbiter617 (The first video I watched from him was hunted) because of him. (Arby created Rise of the Spartans, a video linked up top.)
If anybody is able to find the video, please post a link here. I've been searching for it for the last year or so.