Yes, I know that the "Berbers" by definition speak the Berber language and still follow more ancient customs to varying degrees. The point is that many "Berbers" assimilated into the elite population, and lost their customs and language. So, the Arabic speaking North Africans are not 100% "Arabic" or descended 100% from later migrants. That's not even close. So, in terms of genetics it's not "pure Berbers" whatever that even means, versus pure Arabs.
Yes, I also get that the fascination is with pigmentation, again, and some desire to know if before the advent of the slave trade all North Africans were as "white" looking as the ones who look "whitest" now, like the Kabyles and the Riffians. The answer is that we don't know, and will have to wait for ancient dna.
As to your comments about R1b, yes, one study found R1b at 16% in some Kabyles, but in Moroccan Berbers the highest every found was about 2%, so I don't see how "paleness" can be correlated in North Africa with R1b.
http://www.nature.com/ejhg/journal/v18/n7/fig_tab/ejhg2009231t1.html#figure-title
The paper that typed the R1b in the Kabyles is very old and the R1b designations are based only on STRs.
Arredi et al: A Predominantly Neolithic Origin for Y-Chromosomal DNA Variation in North Africa
http://www.cell.com/ajhg/fulltext/S0002-9297(07)62417-3
"
R1*(xR1a1,R1b1-R1b8)"
As to Mesolithic Spain, there has never been any R1b found. La Brana is C1a2, Loschbour in Luxembourg is I2a1b.
This is a good resource for published ancient dna results:
Paleolithic:
http://www.ancestraljourneys.org/palaeolithicdna.shtml
Mesolithic:
http://www.ancestraljourneys.org/mesolithicdna.shtml
As you can see, Villabruna from Italy is R1b, but none in Iberia.
You don't need to have R1b to have pale pigmentation. There were depigmentation snps present in the Anatolia Neolithic, and no R1b so far.