Here's still another option that was mentioned on somebody's blog:
http://www.aquapac.net/nojavascript/commercialcon.htm
I think it's $ 60. Here is the link to their online store:
http://www.aquapac.net
It's the wire-through electronics case, which you can get to by clicking on the icon for "Radio Microphone and Connected Electronic Cases." Apparently, you can see them at Boater's World Marine Centers, in case a store is near you. Let us know what you decide and how it works.
Good luck!