Brahmins with Vaishnavite Marks in Palakkad villages
Strangely most of the people who migrated to Kerala were iyers (Though I have seen an iyengar family in my own village and when enquired they said, they migrated from Andhra) . While most of these iyers wore Vibhuthi (a smartha custom) , some of them wore Gopi crescent like Madhwas and some single red Oordwa pundra line like the Vaishnavites of Tamil Nadu .(Oordwa Pundra has been mentioned in Vasudeva Upanishad and was in existence from time immemorial)
A.Palakkad Brahmins wearing Namam
It is also interesting to note that the majority of people wearing Oordwa Pundra are from two of the eighteen villages in Palakkad viz Thirunellai (also called as Thiruvilla kadavu) and Pallipuram . Sri Narayana Murthi belonging to Palakkad had written (http://www.narayanmurti.com/3_34_brahmins_of_palakkad.php ) that these Vaishnavites “ came to these villages from Srirangam, Conjeevaram, Srivalliputhur and other centres of Vaishnavism. They were used to the pure Vaishnavite traditions of living, such as Namam, names of individuals, worship of dieties etc. Basically, they were Vadama Smartha brahmins, who worship all Gods, but primarily in the Vishnu aspect. The Thirunellai people also worship Sankarshana, an aspect of Vishnu. All these are external, since they "wanted to be Romans, while in Rome" and they chose to live like Smarthas Some of them said that they also owe allegiance to the Jeear in Srirangam or other Vaishnavite Acharyas and the Sankaracharyas are not welcome in those villages, even to-day. Mostly, they marry only between these villages, until 50 years ago.This has changed completely, now.” From another of my friend, I understand that once upon a time, they never used to say in mamo Partha “Parameshwara preethyartham” but say “Narayana Preethyartham”
B.Palakkad Brahmins wearing Gopichandana
There are also Palakkad Brahmins who wear crescents of Gopi Chandana of yellow colour .All the Brahmins of a small village called Pulakode belong to this category They all wear short crescent with Gopi chandana .Possibly they might have belonged to Madhwa families in Kumbakonam.
Even among those who normally wear a crescent with Gopi Chandana , there are a few who wear long gopis like the North Indian Vaishnavas . Being very much interested in the history of Kerala Brahmins , I had enquired from those who wear Gopi whether they are Vaishnavite Madhwas and they told they were but followed all the Acharas, manthras and ceremonial dress of Smarthas .For all practical practical purposes except for Oordwa pundra they were Smarthas.
C.Palakkad Brahmins specialised in Vishnu worship
There is another small group of people called Azhvars in Palakkad and they do pooja (at least on festival days) in most of the Vishnu/Krishna/Rama temples managed by the Tamil Brahmin. My friend Anantha Narayanan who is a Vaishnavite Palakkad Brahmin says “Regarding azhvar, they are called to do "dwaja arohanam", "avarohanam" in ratholsavam and certain pujas only. “.
Note- I also do not know whether such Brahmins wearing Namam or Gopi Chandanam are there among the Pondi Brahmins and the Trivandrum Brahmins