Smoke Top,
Landrace strains are getting harder to find. Reeferman used to have a few but not sure anymore, Afghan is one pure Indica that you'll find in most modern hybrids and may still be available as a pure strain. Also I understand that several strains from Pakistan are also available...I'm talking Chitral.
Be aware that a pure landrace sativa is going to be a beast to grow. Tall, low yielding, nute sensitive and long finishing. That's why there are so few of them available. I have some Burmese sativa seeds and Yoruba Nigerian seeds...but I can't recall where I bought them. Good luck...
JD