Well, here is the final word from Dan Starman, a partition guru.
Hello ******,
No. The 32-bit limitation for the Starting Sector of any partition (Primary or Logical) would absolutely preclude being able to partition an 8 TB disk drive using the MBR partitioning scheme!
Theoretically, you could fill the size of a first primary partition with close to 32 bits then use that for where a second primary partition starts and set it for up another 32-bits, which should give you close to 4 TB of overall capacity. (You wouldn't be able to have a 3rd Starting Sector that was over the 32-bit value of 4294967295 sectors though; which is about 2.2 TB. So, you're stuck with a maximum of only two partitions!) I wrote "theoretically" because I haven't had access to even a 3 TB disk drive to test what would happen if I did so... I have no idea if the Windows 7 Pro OS would even allow you to access any part of a disk over 2.2 TB if you set one up that way. And if it did, or did not, you should/would also have to test other OSs and various programs which interact with the file systems on a such a disk drive.
TheStarman.
Interesting, I guess that confirms what Saab said and puts the issue to bed.
Mac