If you're hoping it'll get you brownie points, then go ahead and send it. It can't hurt you...the worst thing that can happen is it doesn't get there in time.
If you're sending it b/c you enjoyed your interviewers and want to thank the interviewers, then it doesn't matter how late you send it. So, my final answer is YES, send the cards!!
If the interviewers were nice (and they did take time out to interview you after all), I think you should send a thank you card out of common courtesy. Like everyone else said, it can't hurt you. All in can do is help you.
hey, i interviewed at a school on november 28 and didn't send a thank you note until around december 15. i got accepted so obviously my late thank you card didn't really affect the my status. i would send one...good luck