I'm no expert and will happily be proved wrong on this but I'm fairly certain that the FAT32 4GB max file size only prevents larger files from being read or copied when connecting an external HDD to a PS3 via USB.
I cetainly managed to copy ANH to my PS3s HDD last night via media streaming (over a wired connection - PC > router > PS3) and it played perfectly striaght off the PS3 HDD this morning although I only watched the first 20 minutes!
I have other 9/10GB files (VOBs) on my PC that stream fine to the PS3 over WMP11. I am going to try the same technique of copying them diretly to the PS3 HDD later....