In several cases, new camera models share an existing shell so at least some mention of a housing in progress would be nice. Most consumers don't attend the video industry trade shows where these items are sometimes displayed pre-production.
In defence of all manufacturers, the big electronics companies tend to have a big long line for their demos. They first go for their big market of production houses etc. U/W is still a minor market. So the housing manufacturers are pretty low on the list.
Recently, I even had to give my contact to one of the manufacturers because their Canon rep was slow in getting a loaner camera to them. I've had to climb mountains to get a Sony V1U tester, and I asked in Aug 06! I had to use my industry buddy's camera in Dec because Sony's response was so glacial.
There are are a lot of mitigating circumstances. For instance, housing manufacturers have to gauge the sales of cameras in order to support them (esp camera specific housings like the Sony FX/Z1 etc). I'd been told by a major manufacturer since last Nov they'd build a housing for the HDR-FX7/V1 but they never announced it and still haven't, because they are waiting on the sales figures and also interest level.
As you say, it's easier to deal with the little consumer cameras since they tend to be of similar size. But even those throw in a big surprise once in a while, like the HC1/A1 telemacro mode and the older lanc boards problem.
So it is understandable that manufacturers fence sit until they are sure the product is going to launch. It's pretty embarassing if they had to backtrack on an announcement.
However, I have to agree that the websites in general could be improved on ease of navigation and search.