Still, I think you'll have to unpack the SPB, as I failed to copy the file from the disc due to "incorrect MS-DOS function" - a sure sign that video files are in there. You're going to translate the videos sooner or later, right?
I'd also say that SPB only contains videos, but then why the hell the export versions' SPBs are as large as Japanese's?..
Also, I'd like to know if a properly functioning ULZ unpacker is done - I think the planes' models may be in BPB as well, but thrown off by you as "not textures, thus irrelevant". I've got esperknight's cs files, but one unpacker only unpacks ULZs since folder 0112 (which is a bit away from the target 0080 folder), the other one crashes.