I have 5 or so Nepenthe that were in 2 and 4 inch pots. I have started using 6 inch mesh baskets and 100% sphagnum moss, and my Nepenthes are starting to perform better. The oversize basket prevents them from going too dry between watering, the mesh of the basket keeps them from being too wet and lets air to the roots. When I get organized, I'll post a few images in a new thread.
Hardy - That N. campanulata is really choice. Excellent. I will have to look around for that one.
Newbud, only a small handful of Nepenthe stay small enough for a terrarium, most are long vines, on the order of 6 feet to 40 feet when fully mature. BUT because the US climate is mostly not to their liking, most Nepenthe sit for long periods with little growth, then they have a growth spurt, then as weather cools or warms (depending on species, hybrid & Locality) they go back into a state of slow growth. It can take many years, even several decades to get a Nepenthe up to full size. So while your plants are young, they will definitely enjoy the terrarium. My friend Tom Heller has a N. truncata, and N. raja that are decades old and still have not matured to the behemoths they could become. He is getting 1/2 gallon size pitchers, but not the full gallon size monster mugs they produce in more Nepenthe friendly tropical climates. Zone 5 Chicago is not Nepenthe territory. But over all, they are fun to grow. Most of the hybrids, and maybe half the species are easy enough that us mere mortals can do a nice job with them. Dive in, one can't have too many plants around the house.