Well I just tried the free preview of Inglourious Basterds in "1920 x 800" resolution. No need for an account or anything.

Appox 87MB mkv download for a 1 minute preview. Averaged about 250kByte/sec to Australia so not bad speed wise. The complete movie is ~11 GB. Good quality picture (so a Blu Ray rip most likely) and DTS soundtrack that streamed through my MythTV box to my receiver.

That said this movie is out on DVD etc compared with Avatar which as mentioned basically has to be a handycam job.