I think I know what you want to achieve, and I think it won't be possible:

With all the different figures, different material zones, and most of all: node setups, it is almost impossible to write a "one script covers it all".

A simple example:
I made a figure which has several "options" attached to the diffuse map, like makeup, blushing/sweating, lip's moisture, and whatever.
This is all in a shader tree which also includes SSS, specularity and whatever, and it would be a nightmare to edit manually.
But "I was smart and added a lot of blender nodes" to easyly swich between the options :/

Good so far.

However, if you write a script that shall hunt down the specific node which you want to change, your script would have to have some kind of AI - in order to determine what each node actually does, and which node is "THE ONE" which must be modified.
It also must account for the settings of the blender nodes, i.e. which part of the shader tree is current.

Now back to the initial problem of identical material naming:

I model a bird with "wings" and "legs/feet/claws"
Next I model a whale, which has "flukes" and "fins"
because I have nothing better to do, I spend the rest of the week modeling a centipede: no "arms" at all, but lLeg1 + rLeg1 up to lLeg100 to rLeg100.

Any idea about a common naming convention for these three?
And I don't even talk about tails here, though some animals and male humans could eventually share some here :D

Summary:

I believe that such a script can be coded, and it would probably be of great help for people who frequently work with a particular figure.
However, I see no other way than that this script must be written for this particular figure, and all it's particularities.
Anything different in other figures would break the script, because it's nearly impossible to cover all eventualities (as I described above)
So a "personalized" script would be necessary for every original figure, and all it's particularities, and 100 legs or wings...

Peter