I just ordered a kirk L-bracket for my 5Dmk3 and on their website it says that it is a preorder. I'm going to call on monday and see when the ETA is, bt thought I would check here in the meantime to see if anyone has already talked to them...http://www.kirkphoto.com/L-Braket_for_Canon_5D_Mark_III.html
FYI, I'm using the L-bracket, their long focus rail, another quick release, and a novaflex pano plate to make a very lightweight, relatively cheap pano/nodal point head, for pano as well as vertorama. Pic below (idea from Klaus Herrmann) note, L bracket not for D90, for 5Dmk3 hence the point of this thread. Also, I haven't ordered the novaflex plate yet, does anyone have an idea for a similar option for cheaper? It def needs to lock, and if it had clicking rotation points that would be a big bonus. The novaflex is around $191, so it would need to be either similar or better for cheaper.