We do plan to have a cage for the Nikon D800! The design process is already completed and we plan to start shipping them in late March. For a current list of cages and estimated shipping dates you can visit this page – http://www.letusdirect.com/cart/mcs-availability.html

As for the D4 we have not decided yet if we ill be making a cage for this camera, but if you would like to suggest/vote for it, you can do so here – http://brainstorm.letusdirect.com