well actually,there is some info on the newar connection besides dr thundy's article... abook on history of nepal by messrs bajracharya and co.there is also a book" the todas" by w.h.r rivers which connects todas to nairs and nambuthiris. there is also a book- " a short history of kerala" in which the author k.v.k ayyar connects nairs to the arrathas and bahlikas of the era of the mahabharatha...so some literary evidence  exists and that aratta theory gives a lot of support to the scythian origin theory because the arratas were possibly a saka tribe