I am working with a Dangerous Things xNT NFC device, and I just tried out the TapN app
. It enables me to long press on the LastPass password field and then tap my NFC tag to the phone to enter the password. The app description states the password is stored in such a way that it cannot be decrypted with only half of the pair (NFC tag + phone).
Seems to be working well for me so far. Might be worth a look.