Depending on what you want, you could easily get to $4k... but that's a lot more than you need.
I've used most of the major players in the video housing arena (Ikelike, Gates, Light & Motion, etc.) but have only tried the ikelite for dSLR. It worked fine paired with a 20d and probably the most affordable option. Sorry to hear of your friend's issues - bound to happen with as much production that they do. The 400d is a new camera too, so maybe there were some bugs to be worked out with the new housing design. Even so, that's horrible build quality.
All that being said... I'll probably go for the ikelite despite problems. Gonna go down to
http://backscatter.com/ and check out all the options to see what's the best fit. The smaller the better
