I agree with all of the comments about the RRS LR clamp. It is fine with RRS plates, but it is also worth pointing out that it is incompatible with Arca products themselves. For example, it will not lock down on the rail of my Arca F-line.
On the subject of ballhead alternatives to Kirk, Arca, acratech RRS,etc., I would not dismiss the Linhof Profi ballheads which will also take the RRS and other clamps. I also recently handled two others, Giottos (poor) and a head from a German company called FLM. This was very solidly made out of metal and is similar in design to the Arca, except it has a metal ball like the Linhof. It comes in different sizes and is surprisingly cheap. It can be bought without the platform and in the UK is available from Speed graphic.
When it comes to tripods, nobody ever seems to have a good word for the Manfrotto carbon models. I have a 440 with the carbon 544 levelling base/column. Great travelling tripod and I so much prefer the flip-locks on the legs to those dreadful twist locks on the Gitzos (I have a 1328 and a 1349 as well).