So it is possible as far as you know... I'm also curious about doing this for my subway RFID card. Man that'd be useful.

At my office I've got a number of RFID door locks that require I attach this bulky plastic card to my belt. I would rather program a ring such as these to carry that signal. Is there a way to tap my ID tag card to a device that would read the unique identifier and then program an NFC ring with the signal? Mind you, I know very little about this technology (but I can learn).

Perhaps a good secondary product for you guys would be some kind of NFC console that grabs signals from one source and programs the ring with them..