Zdziarski’s Blog of Things has an article about possible enhancements to iOS security, in the wake of the Apple vs FBI affair.
Another idea is one I’ve mentioned before: Duress Passwords
If you are asked to unlock your phone, you could use a different finger, the duress finger, and the fingerprint sensor could appear to accept it, but erase the phone. If you enter the duress password, the phone could erase itself or, perhaps, just start recording what is going on and uploading it to the cloud.
Another idea are Landmine Passwords. These are passcodes whose purpose is to defeat brute force searches. If you avoid landmines within hamming distance one or two of the correct passcode you would have litle chance of hitting one while trying to enter the correct code, but any searcher would be very likely to hit one before hitting the correct passcode.