I have two players who want to play goliaths in the next campaign. I know that they are not Realms-specific, but I recall an excerpt from a recent novel which featured a goliath.
Barring that, how can I introduce goliaths to the Realms?
The novel in question was Depths of Madness. 'Twas written by Erik Scott de Bie, who was one of the sources of the above info. The other, Tom Costa, has done some Realms stuff and has some excellent unofficial Realms material (some of which later became official) in the Realms Bestiary, Volumes 1 & 2 by Eric L. Boyd and Thomas M. Costa. His Prestige Classes, found in Tom Costa's Prestige in the Realms, are also highly recommended.
Also, you may want to check out Champions of Valor. That particular tome references [on pg. 17] several locations around the Realms as places for inserting goliaths into an FR campaign. The section also offers suggestions for how goliaths came to be, in the Realms.