From what I hear, someone had the full 2 minute+ trailer, and uploaded it. I saw that on the Gamefaqs.com FFVII messaggeboard, but when I tried the site it said the users account had been banned.
The guy fighting Cloud isn't Sephiorth though, as we can guess. Some have said Rufus, while others have suggestes that the man Cloud is fighting is actually Jenvoa, seeing how she can take the form of whatever she wants. From what they understand, the guy has some relation to Sephiroth, hence the sword, same hair colour, and One Winged Angel playing the background.

If anyone gets any news on new trailers then let us know straight away, rumour has it that Square will release the trailer to the public soon in its proper quality. I think the only one available still is the 5mb 20 second one, which I have saved by the way, if anyone wants it, not sure how I'd get it to ya though.