If you want an example of a ringing choke converter, grab a cheap disposable camera and extract the flash unit from it. The tube itself will be useful for the timing light but you'll have to beef up the converter to get the flash repetion rate higher. Basically it is a transistor switching current to a primary. There are two secondaries on the transformer - a couple of turns to feed the base of the transistor and the actual high voltage secondary. There normally another transistor fed via a zener diode connected to the rectified secondary circuit to sense the output voltage. When the output voltage is high enough, it turns the mains transistor off. The 'scream' after the flash operates is the converter working as it charges the flash capacitor. Troll the web for something like 'xenon flash' and you should stumble upon something. Or as I suggested earlier, grab a commercial timing light (a cheapy in australia can be got for around $20USD).

As for ion sensing ignition, SAAB did this in some of their road cars. I'm not sure if they still do it. Theres been a lot written about this technique and the strategies for the timing correction.

My choice would be an AVR (hiss hiss!) as I've done code for a tacho already (in C and asm).