Alright, I just tested.
A CECHA-01 running stock 4.89 can recognize SD-XC cards just fine. The only limit is that they have to be FAT-32 formatted; while the "standard" for SD-XC cards is ExFAT. My PS3 happily recognizes my 1 TB SD-XC card just fine reformatted as FAT-32, and will play photos, music, and videos off it.
It also recognizes a 2 TB FAT32-formatted USB hard drive no problem on the front USB ports. (Note that it can't recognize anything larger than 2 TB because FAT32 doesn't support >2 TB without breaking things.†
That means you could have up to 12 TB of storage poking out the front of your PS3. 1 TB SD, 1 TB Memory Stick (although there were never this capacity, so you'd need a microSD to Memory Stick Duo adapter,) 2 TB CompactFlash (again, nobody made/makes a 1 TB CF, so you'd need a CF-to-SD adapter, and there are dual-microSD-to-CF adapters, so you should be able to get 2 TB in the CF slot,) plus four 2 TB USB hard drives.
If you wanted purely "stealth," you'd have to cut it to 8 TB, by using the ultra-small microSD USB adapters DeViL303 shows which would only support 1 TB microSD cards. That would cost you over $800 to outfit, though, since 1 TB microSD are hovering right at $100 each.
†More specifically, it is the "Master Boot Record" partition table (MBR) that tops out at 2 TB. To exceed 2 TB, you need to use the GUID Partition Table (GPT) that more modern UEFI-based computers use for hard drives; the PS3 doesn't support GPT, only MBR. So even though you *can* format FAT32 >2 TB, it needs to have the GPT layout, not MBR, so PS3 wouldn't support it.