[Sheepdip]

Sounds like a ignition switch problem, but before throwing anymore parts/money at it I would start with testing the ignition switch. Get a good ohm meter if you don't already own one, unplug and remove the ignition switch itself and go to town proving it's good, including giving the pigtail that plugs into the back of it a good visual that it hasn't got hot and melted losing isolation between contacts. If the switch proves good move on to the wiring.