After my extinguisher exploded, I found a BK mount and halon extinguisher on eBay for $100. It was well worth the money, but hope and doubt I will ever use it, but it does look great under the passenger seat. If anyone is interested I saw this BK mount on eBay today, it's a fairly good price considering what the mounts sell for new:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=150405542010&viewitem=&sspagename=STRK%3AMEWAX%3AIT#ht_500wt_1035