Idea #1

Have you ever heard a story about someone who has lost their cell phone then ends up with a $26 000 bill? There has been a couple of these stories in the news lately and in both stories the cell company has forced the customer to pay up. Your phone doesn't even need to leave your possession to be a victim anymore. Do a Google search on Sim cloning or bluetooth jacking. You'll have to figure out the rest for yourself.
The idea! You know how if you start to make mysterious purchases with your credit card it stops working until you talk to the credit card company. Try buying 3 tanks of gas in one afternoon to test this out. Anyway...How about some software in the phone system that identifies if your calling patterns are erratic. For example Mike Smith from Vancouver is suddenly taken an interest in calling Beijing.
Say you make a long distance or roaming call outside the normal list of numbers that have appeared on your call history in the last 12 months it automatically forwards you to a automated system where you have to give a pin number or your birth date etc, therefore verifying the user. I know asking the telecoms and wireless companies to update the phone system is absurd. That would mean a change at the core of the phone system...god forbid.
You could also implement this as an app in the phone. Whenever a new number/roaming/long distance/international call is made it would ask you for a code or use a voice recognition safe word.Then the phone companies could really hold you to your $26k bill!
Somebody build this.
The network side solution would be better cause it would curve sim cloning and bluetooth jacking fraud.