Today me and georg looked at the g_male rig, specifically at a unique aspect in the control points, it has this ability to control one aspect from differnt locations, the main application of this that we where after was the ik/fk blend, the rig allows us to change the blend from anywhere along the arms controls. after some poking and proding we established it was a shape node with added atrributes, the special thing about it was that it was an instance, this fact stops the ik and fk from concatonating the two switches i.e. if both switches are set at 1 then the way I initially approached the solution it would be 2, this errors the rig's arms, but with the shared attributes being an instance its the same accross all the different nodes, so if its 0.5 in one place its 0.5 in all.
brief description out the way heres how to do it;
decide what it is you want, my arms shared attributes will be divided between hand and arm [arm is the ik/fk switch, hand is the grip, indexCurl spread, indexSpread etc.]
make a shape, I quite like singe vert curves as there tiny and can easily be hidden in the scene.
rename the transoform node appropriatly for the section its going to be shared accross i.e. sharedAttr_lf_arm_master_01
select the shape not the transform
add attr [modify > add attr] and edit parameters parameters [channel box]
duplicate special the shape node as an instance.
select the shape then the object you wish to impart the new attributes.
run the command "parent -r -s" [no quotes] or make a button in the shelf that does this command.
And done, the object will now have the shared attr.