Aqualarm made-up a custom panel for me with three bildge alarms (sail locker, main, and engine compartment); and, two flow alarms (main engine and generator). The people at Aqualarm were very easy to deal with. I called them a few years ago with a question and they were still very helpful. They used to make-up a custom panel for very little premium.

https://www.aqualarm.net/comerus/store/comersus_listCategories.asp
http://www.aqualarm.net/comerus/store/comersus_listItems.asp?idCategory=52

http://www.defender.com/category.jsp?path=-1%7C311&id=1236056 will give some idea on the sensors (which you could rig-up yourself, though I think getting the package from Aqualarm would be simplier and pretty easy.)

West Marine also will provide you some items, if you want to go there.