The pure sugar cane root beer is called TeXas or something like that (the place in Dublin use to make Dr. Pepper w/p.c.s.). The p.c.s. makes it a bit sweeter than most root beers (I.B.C., Frosty, etc.). I don't remember what brand it was but I think I've had a root beer that was rather medicinal tasting.
There's a local candy store here that has a room filled with oddball soft drinks. About 4 shelves were filled with root beer so there's a lot to check out.