Two ideas:
What about paired hardware? Imagine buying an iPhone and pairing it with your charger and they share keys. Any other charger used would immediately wipe the phone. There could be settings to tweak this.
what about wiping the phone if it has not been logged into a certain amount of time with a certain password (not normal PIN)?
The current crop of phone busters completely bypasses the 10 wrong pin and wipe option. The idea is to immediately wipe the phone without using Find my iPhone (defeated with airplane mode).