I think that Jackson's King Kong has been the only Kong without a sequel (so far). The original had Son of Kong, the 70's King Kong had King Kong Lives and even King Kong Vs. Godzilla had King Kong Escapes.
King Kong Escapes is not a sequel to King Kong vs. Godzilla. Even though both movies are made by Toho this film film was a loose adaptation of the Rankin/Bass Saturday morning cartoon series The King Kong Show and was the second and final Japanese-made film featuring the King Kong character.
In King Kong Escapes he is depicted as the normal size for Kong and not the larger size that was used in the movie with Godzilla.