From what I'm googling, and judging by the confusion over chip frequencies, the people to talk to would be, like, ham radio hackers. I am certain someone smart in china could come up with something that will at least pick up the presence of a chip, and let us have it at an affordable price, without patent ransoming.
======
Hmm, they already have, 1st google hits for those frequencies lead to China -
http://www.rfid-in-china.com/products_700_1.html http://www.rfidshop.com/passive-low-...42khz-10-c.asp