A friend wants the new 27", but wants to add his own SSD in combo with the stock 1TB drive. Then Fusion them. That would be cheaper and larger than having Apple do it. So the Q is: Can that be done? I poked around and couldn't find an answer. THX!
According to presentation image of iMac's internals there's no space for another 2.5 or 3.5 drive. the only way to have HDD+SSD combo in new iMacs is to install rMBP-format blade SSD drive into it. Which makes your friend being unable to use his current SSD.