I've seen this also. What could be happening is the ignition lock cylinder is turning slightly from the run position, especially with a lot of keys on the ring.Also when the radio and turn signals go out, wiggle the key, do they come back on? Sounds like an ignition switch issue. I have seen it before, I work on them for a living. Good Luck.
If you can reliably reproduce the problem it will be easier to trace key points with a voltmeter.My problem, when driving and I hit a big bump, my radio and turn signals stop working. But if I pull over and shut the truck off they work just fine. What could the problem be?