Upload & Sell: On
Now that we can see it, I generally like the looks of this design on the Really Right Stuff L plate for the 1DX. I had decided to go ahead and pre-order one before seeing this, and am glad I did. I agree with Lars that the bottom does not look much thicker if any. But of course the weight is up in that area becasue there is less hollow out on the bottom because of the sliding side arm.
I have a slight concern with how stable the side arm will be, and will wait to inspect things when I get one, but it is likely fine. I do like this approach much more that the design that uses two side screws to attach the side arm. I have been trusting RRS with my L plate business for a long time, and expect to continue that. I do like the capability to use just the bottom plate only, and thus the dual use will save me buying another bottom only plate. And obviously a lower weight would be nice, but I think I will survive with this. Because the 1DX is a camera that will exist in lower quanities than most other Canon's, I can see why RRS would not like to also make a light weight one piece slot adjustable L plate, but I do think there is a market for one. With little tooling needed, and using CAD design, and CNC production, the cost to offer a lighter weight L plate would not be too high, so perhaps it might happen some day. They could even work on extra machining in the design to make the weight very low, but that would keep the cost high, which is also a factor in any success of another plate.
Note the big change over all previous 1D series L plates from RRS where the side arm and its dovetail are moved forward toward the front, rather than staying way back. This puts the camera in better balance when mounted on the side arm than it was before, and likely will work out fine. They included a loop around in the design for where the remote release needs to clear, and that loop around means there is no need for a full gap in the side arm for the remote that is used in some RRS plates. But by having the side dovetail out far enough for an AS clamp to clear the remote, this plate does stick out further to the left than the previous plate for the 1D4, which in that design could be positioned to either be closer to the camera, or be out far enough to clear the remote. That makes this plate have more metal in the side arm, contributing to the weight.
The forward position of the side arm will likely not get in the way of anything, but I guess we will find out soon if it does. And that forward positon makes the side arm kind of a mini grip for your left hand, which may be nice in some cases or for some people.
I hope the real production units have the index marks for lens center on them, because I do use them some times. And for this design there only needs to be one for each leg, and they can be accurate, because there is no slot on the bottom to slide the whole plate in to different locations. This is likely photos of a prototype that did not get the index marks put on. I also hope that RRS updates their photos as required to show those, or to show any other little details that might apear over the life of the product. They have been lapse at times in the past about doing that.
Also note that there is no provision to attach a hand strap to the right side of the plate. That is not something I use, but I know some people do.
So when people get them in their hands and on their cameras, please let us all know what you think about some of the issues that have been raised so far in this thread. My plate will not be here for at least several more weeks, so I will not be of help very soon.