Does N. rafflesiana really need lots of humidity and warmth to grow and pitcher well? That giant form that I got a month ago has only produced 1.5 leves, But it was on a west window, then damaged during moving, and is now under two 150 watt halogen bulbs, with 55 to 65% humidity. The temps. range from 68 F at night, to about 78 F during the day.
Part of the problem might be the stress the plant has endured. Nepenthes are notorious for going into temporary shock while being shipped and knocked around. But...you could probably improve things by boosting the temps and humidity a bit. Rafflesiana likes it warm and humid. Oz