Sony's model naming is just the worst and most confusing one they could have possibly come up with. They might have done this on purpose ... but well, that doesn't solve the problem.
Not only do they name their models with the HDD size - which makes no sense at all as the HDD is upgradeable with any laptop HDD - but even consoles with same HDD aren't the same across regions.
So I propose a new model naming ...
v1: no flashcard ports, 4x usb, GS+EE+RDRAM PS2 HW (like the NTSC/J and NTSC/U 20gb)
v2: flashcard ports, 4x usb, GS+EE+RDRAM PS2 HW (like the NTSC/J and NTSC/U 60gb)
v3: flashcard ports, 4x usb, GS PS2 HW (like the PAL 60GB and NTSC/U 80gb)
v4: no flashcard ports, 2x usb, no PS2 HW (like the NTSC/J, (NTSC/U) and PAL 40GB)
I guess v1 and v2 could be seen as one version as the motherboard is the same ... so maybe they should be named v1.0 and v1.1?
Let me know what you think of the proposed naming...