Either go with the Pertronix or find a '79-'80 ZX dizzy in a boneyard with an E12-80 module and run it. Those are probably the two easiest/most cost effective ways of doing it.
The 280Z distributors use an ignition module that's mounted inside the passenger compartment. The later N/A ZX distributors have a different 'matchbox' ignition module mounted on the dizzy, an E12-92 or E12-93. They can be used, I've got one running properly on my car now, but it takes some thinking to get around the timing retardation built into the later units. Another good option is to run the Ford EDIS system but that's probably a bit more complicated than what you're looking to do.
Come to think of it, I've got a spare early ZX dizzy that I rebuilt last week, but I haven't tested to see if the E12-80 module is still good.