I believe these are S1's of the Lemon Thai Ko Sumui, from Thailand that Sonic got from a friend. He really loves this one, I've been wanting to grow it for a long time also, ever since he mentioned it. Hope this helps.
I hot some of Dutch Flowers Lemon Thai as well as some Thai stick seeds from the early seventies. Great smoke and good yield but not that good of bag appeal on ether of em as they take a long time to flower and have fluffy buds.The Dutch flowers I think is a hybread and the Thai is an ILB.