Since <keygen> et al doesn't support the deployment of PIN-codes I haven't yet tried creating a java KeyStore with password protected keys.
Is there actually any support for per key PIN-protection in Android?
As a side-note all bank-related keys come with a PIN-code including the BankID Android app
( http://support.bankid.com/sv/supportbankidcom/Mobil/Systemkrav-Mobilt... )
but I guess (it is completely secret/proprietary...) that BankID use some kind of home-brewed key-store.