A pretty common technique these days where one species or hybrid is a cool grower is to graft that plant onto a more temperature tolerant rootstock. It's often observed that a heat tolerant rootstock confers greater temperature tolerance on the grafted plant. If anyone wants to discuss possible mechanisms I'm open to it. For example, for Passifloras, people graft cool growing species/hybrids onto temperature tolerant species such as Passfiflora caerulea (or its hybrids). The result is a grafted plant which can grow under conditions where its ungrafted counterpart could not.
Like Nepenthes, there are many species of Passifloras from high elevations, in particular many stunning Andean species from 2000-3000 m near the equator (Tacsonias). Most such plants can only be grown successfully in the mainland U.S. near the coast in California. An example of a Tacsonia, Passiflora 'Mission Dolores', a hybrid between two high elevation species, P. parritae and P. antioquiensis, is shown below. Flowers are 7 inches, peduncles are up to 2 feet. Fruit is edible (and tasty). Perhaps it's obvious why people would like to grow such plants in places beyond such a limited range.
Like Passifloras, many of the most striking Nepenthes species are also from high elevation. Has any effort has gone into grafting these plants onto temperature tolerant Nepenthes rootstocks?
I realize grafting Nepenthes is no doubt less straightforward, with less material available than for a rapidly growing vine. Still, I'm sure people have tried grafting Nepenthes. I would emphasize that grafting is a technique that those who are skilled can perform on even the tiniest seedlings.