The Metz IIRC is a 6V unit. What kind of batteries does the Nikon use? I can't imagine this is a stock item. If the voltages even match up you'll have to find somebody to make one for you. Which will end up costing more then it's worth most likely. Why not just use the 60?
I believe the Metz 60 series is a high voltage unit, although it powered by a 6V battery the output is about 360V. I can measure my unit again to make sure.
I believe the Nikon has a high voltage outlet, just not sure about the compatibility with the Metz or cord option. Since it works with a Quantum turbo or lumedyne battery (not sure of those voltages either) I am hoping it's Metz battery compatible.
What you're looking at in the Quantum batteries are low voltage output.
The Metz delivers the high voltage because the Metz flash was designed for it.
The aftermarket batteries just gave you much more power at the same voltage as the original 4AA batteries.
You can save yourself a lot of headaches by going with one of the Quantum batteries and the proper cord. I've used the Quantum Battery 1 with Vivitar 283's with excellent results(more flashes) and the same battery will work with your flash with the proper cord.