Probably the blu-ray film is way to huge to hold on a PS3 HDD.
The easiest way, and probably only way would be to store the film on a seperate machine and use that as a media server. However, I dont think anyone has tried doing this.
true, just grab them in 720 or 1080 use mkv2vob or similar tool and them either stream them through ur home network or copy across onto the ps3 hard drive