I received the RRS (Really Right Stuff) L bracket for the D3 a couple day a ago and just tried it on today. I ordered this at the beginning of December and it took a month to get, I read they were swamped with orders.
The bracket in my opinion is the worst bracket I have ever ordered from them (D100, D2x, lens plates, etc). The 2 doors above the battery really can't be accessed easily without a tool of some kind to pry the door open (bracket too cramped). The bracket itself protrudes too far in front of the camera and feels horrible in my hands as opposed to the D2x L plate which is perfect. They did not round the stock but instead cut it in a square shape, see here (not my images but another user with the same complaint);
Well, I got my RRS L-bracket and have to say that I'm not nearly as disappointed as I thought I would be. Don't get me wrong, the thing doesn't even come close to fitting as well as the one for the D2X.
I've had it on for a couple weeks now, and I don't notice the difference in contour because I never have a hand on the left side of the camera. It is always on or under a lens or some such. I don't open the doors on the left side either so that's not a problem.
Of interesting note is that the bracket fits the D-300 with battery grip just as well as it fits the D3. Of course that could be considered either good or bad depending on how you look at it.
The fit isn't great, but it does the job.
My BIG complaint is that I ordered it when the site said "now shipping," and I went for expedited shipping. Well, a month later I finally got it. I did notice on the invoice that I wasn't charged for the shipping upgrade though.