Most housings are quite easy to repair in the field - even without special kits - as long as you have the tools. On our recent Bahamas trip one of our group had a major flood in his subal (the most water I have seen in a housing for a long time).
It fried the leak detector and the TTL circuitry (so it wasn't all bad!) but I was still able to rewire and solder it up and get it working again. Most housings have synch plugs that are quite well sealed on the inside of the housing. And nearly all boats and resorts are going to have soldering irons etc (in fact Jim Abernethy gave me the choice of gas or electric!), so repairs, even without kits aren't too much of a problem.
Luckily that photographer had a spare body so was able to keep on shooting.
Alex
This is quite a timely thread - I am in the process of getting my D200 setup in addition to my already housed D70. Haven't quite decided yet on which housing, but I should have it within the year.
Having a second camera and housing for major trips for me is going to be important. Most trips so far (Mexico, Bahamas, Roatan, etc) are reasonably close and while if I lose my camera, it would not be the end of the world. But I do have a trip planned towards the end of 2007 to Truk and Palau, and if my camera died along the way, I'd be quite distraught, to say the least. And as well, having a second camera for topside is a bonus.
On my last trip to Roatan just recently, I had a minor flood with my D70. The nut that holds the bulkhead connector in place on the back of my Ike D70 housing had come loose. This was probably due to repeated soaking in rinse buckets aboard boats as the engine vibrations may have loosened it. I noticed water entering the housing at the end of one of my dives, so I ascended and was able to save the camera, and more importantly, my lens, from any real damage. I was lucky.
I contacted Ike service and informed them of the problem. They told me that that nut was not something that normally needs to be checked. But apparently it is. So now I check it periodically.
Anyhow, the point it, floods can happen. No matter how careful you think you might be. So, a backup is coming with me to Truk....