I am in Kerala and is looking for a traditional yoga ashram to do my teacher training. I went to one ashram in neyyar but is so crowded and just ok. I read about a place tulasidalam yoga ashram. I hear the guru is a woman and the course is on traditional ashtanga.
Hope you'll find an info here: http://www.india-yoga.com/html/ashram.htm
you may ask these peoples they have been through this stage( they have taken some tranings in south India).
Let me know how many days/weeks you intend to spend learning Yoga.
Also note that it costs a lot to learn yoga specially for foreigners.
The one at Neyyar dam is a reputed one.
There are courses for Yoga teachers training for 6months.