Buy a Shintai calligraphy wall scroll here!
In the context of the Japanese Shinto religion, shintai/shin-tai or 神体 is an object of worship believed to contain the spirit of a deity, typically housed in a shrine.
This may not the the Shintai that you are looking for. This is NOT the Shintai massage technique.
身体 (body/health) and 心体 (heart/mind body) also romanize as Shintai. But I don't know what Saul Goodman is referring to as "light body" though the second character should be 体 which means body.