I was just looking for custom wires and found that Magnecore should be able to help.
From their website:
"Any part of a Magnecor ignition wire can be purchased separately. Loose ignition cable (any type), boots, terminals, professional quality crimp tools, numbering sleeves and wire separator looms are available for installers preferring to assemble ignition wires in their own workshop and at the race track. No minimum quantity is required. However, please remember the Magnecor USA factory and the Australian and UK importer/distributors can supply custom tailored complete wires at short notice."
So either buy the parts and make your own or just tell them what you need and they can make a custom set. If you talk to them about it let me know what you find out.
Glen