I think most of the major players in the UW housing market are working on housings for the D4. I suspect that there will be lots of announcements in the next few weeks (now that the camera has shipped). Most have been working on housings designs since the camera was announced, although most manufacturers like to see a proper production camera before publishing their designs. Just in case there are a few last minute changes from Nikon.
I think they will all start showing their housing designs in the next few weeks. With the actual housings being available by the summer. The summer is a vague date - I use advisably! Hopefully it means housings in people's hands by the beginning of summer (whenever that is!). You also have to factor in that the housing manufacturer's all love to claim that their housing is out now - when often the forums reveal that actually that means you can pay now, but you won't get it for a while!
I am excited to see the solutions they produce for the D4. Most of the controls are standard, although I am pleased that zooming in when reviewing images is no longer a two handed affair (which is a pain in housing), as it was on D2 and D3 series. Of engineering interest is who in particular offers connectivity or at least space for the connections on the left side of the camera.
I am also interested to see if anyone grasps the nettle regarding optical flash synch. With both the D4 and 5D3 not having built in flash - someone needs to take the lead here. Many photographers liking the advantages of fibre optic synch, it would be great if housing manufacture's gave the option of optical synch (not for all flashes and not for all shooting - but flagship models need flexibility).
The technology is there (with systems like Hedwig's - all the housing manufacturer's would need to do is leave space (not much as it is about the same size as the standard hotshot) and more importantly install an optical bulkhead. Easy to DIY - but for a flagship model - it would be good to have options for expansion. Of course, these electronic to optical flash synch converters are manual only at the moment, but still nice to have. Maybe someone may even try an make an optical TTL version, which could be a game changer.
The only delay for the D4 housings might be the D800. I think that most housing manufacturer's are aware that they will sell far more D800 housings than D4 housings, just as Nikon has more D800 orders than D4 orders. And maybe the D800 becomes more of a priority if D4 housings are not finished soon. Hopefully not, though, as the controls are similar enough to allow plenty of side by side development.
I know plenty of rumours about D4 housings being worked on. But would rather let dealers and/or manufacturer's come in with an official line (as Paul has kindly provided above).
@ David - this link shows why Predrag needs a D4 and that frame rate, as he's not a typical underwater photographer:http://www.extreme-p...m/sequence.html