Jabberw0cky,   The Dell part umber for 330-8625 is N8MVT, but that appears to be the sku used when configuring a new 124t, so I am not sure if that will complicate finding it. Now kit 330-8631 or 470-ABFM look to be the active kit with Dell part 60V4V, which both kits look to break down to cable W390D.   Let me know if this helps.     
I'm helping to refurbish a few community centers and they have some older equipment that I'm working on upgrading.  They have an old Powervault 124T LTO5 with a bad 6GB SAS cable.  All I have is the 330-8625 part number, but I need the Dell part number (like YJXMR) to order a replacement.  I have only found one company online that has the 330-8625 part number, but they are out of stock. Can anyone help with this part number conversion?
Part number for SAS Cable, 6GB, Ext tape, 2M (330-8625)