I've been looking at adding one (maybe two) as well and my biggest two concerns is that I'd like to be able to test it and I'd like one that is aesthetically appealing (just redid my electronics!). I haven't found exactly what I'm looking for just yet but did see this from New Wire recently.
High Water Alarm Kit for Boat. High Bilge Audio and Visual Alarm to Alert Rising Waters. Easy to Install. All in One Kit. In Stock Now. Worldwide Shipping.
newwiremarine.com
Here is the old thread I had started on the same/similar topic:
I installed the Johnson High water alarm several years ago and very happy with it. Can turn it off if needed in case you are cleaning the bilge and get it wet...
www.greatgrady.com
