Parts&Sources

Motogadget Digital/Analog Speedos
http://motogadget.com/en/analog-gauges.html

http://www.flatracer.com/#/bmw-airhead-faq/4533419626

plugs & Plug wires

The plugs are indeed non-resistor plugs, the most ubiquitous of them is the NGK BP6ES. (motoelekt suggests NGK BP7ES for all airheads – see link below)
For plug wires you simply need the NGK plug caps which are 90 degree 5k ohm screw on caps which also should be easy to find I would think (stated by someone who has never been to South Africa so what do I know) and a 20 inch (per side) piece of 7mm Hypalon or Silicone jacket stranded wire core plug wire (not carbon resistor core). Simply unsolder and remove the connector at the coil end of your existing plug wire and solder it to the new plug wire, transfer the boot, and screw in the NGK plug caps. Voila you have a new plug wire!
I have found it is best to solder the old connector for the coil end (or use a new one as we do) rather than use a crimp-on end because the crimp-ons often don’t fit the coil well and you have arcing.

 

Ignition

We’ve been using the Dyna Ignition Booster #DBR-1 for a long time with excellent results. It’s compact, inexpensive and very easy to hook up:
We keep them in stock. It’s perhaps not as exiting as a whizz bang ultra cool programmable multi-advance curve crank driven high Z electronic ignition with a name derived from the Greek alphabet, but it’s reliable and it works well…….as boring as that sounds. haha. 😉  We retail the Dyna Booster for $86.99, you of course get the premier southern hemisphere discount. 😉
I actually liked the 79-80 points with a booster, most reliable setup I know of, albeit not terribly sophisticated. The booster takes the load off the points so they don’t wear, they just become a low amperage switch.
If that doesn’t float your boat you could install this:
 
Also have a look at Anton Largiader’s site on Airhead ignition:
Also have a look at: