Indeed, there is no such limit on the PS3 hard drive itself. I've copied 4+GB files onto DVD-RW (UDF mode) and transferred them to the HD easily. I also had a 6GB file I copied from my comuter to the PS3 successfully (took a LONG time over wireless). And yes, they are readable and watchable!

Although I haven't done it myself, I suppose one could separate out the m2ts file from Ady's release, copy just that to a DVD-R DL (UDF), insert the disc into the PS3 and copy it to the hard drive in that manner. This would, of course, waste a disc. But out of convenience, the film would be on the HD ready to go at any time!