Well as a guy who has several ZDZ's, I wasn't too happy when TroyBuilt picked up the ZDZ franchise from RCS. I kind of figured this would happen based on recent experiences with TroyBuilt as well as what I've seen on various forums about how things have changed at that business.
For what it's worth, the engines are still being made and I think you can actually buy stuff from ZDZ directly although I'm betting the shipping charges will be a bit much. The other thing is that those plastic mounts come with the ignitions and I don't know if they are sold separately or not? Seems like I tried to pull the sensor out of one to see if I could get away with a smaller hole in a firewall and the experience was quite a hassle IIRC but it's been a long time.
http://www.zdz-modelmotor.cz/en/
If you do wind up looking at a new ignition, you may want to consider going with a CH unit from the folks out in Wyoming and they'll also change out the sparkplug type/cap if you want so you don't have to run that nasty tapered thread setup ZDZ uses, uses a CM-6 like DA.