Closer to home, this one is for sale in Washington http://www.wmrra.com/forums/showthread.php?18174-AMB-transponder!
found a bunch for sale on Ebay...and if you get more than 5 he will give you a deal. http://www.ebay.ca/itm/152552378141?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT