I've just insured all my gear with DEPP (based in the US, covers worldwide):
http://www.awryinc.com/index.html
I don't have a rebreather yet but anything over $5000 US, you just add an extra premium. It's one of the very few insurance companies that cover flooding.
For more info:
http://www.diveoz.com.au/discussion_forums/topic.asp?TOPIC_ID=17209&SearchTerms=camera,insura nce