Just something I thought I'd mention, and in no way meant to insult your intelligence, but I just wondered if you tried turning the wheel slightly during your attempts to see if it was just that the steering was locked? I know that I sometimes end up locking the steering if I use the wheel as a brace while stepping out of the vehicle, and if I forget that I did so unintentionally, I'll come back to the car and wonder for a few seconds why I can't turn the key. While your ignition switch probably could use a replacement just because, it'd be a few bucks saved if you find that the issue was something as simple as this.
