Nepenthes sibuyanensis X ventricosa is a hybrid between two highland parents. Pitchers should be good size when mature due to the N. sibuyanensis as a parent. I grow it outdoors as a highlander and it does fine. It's been a moderate grower so far. Exotica Plants has done some nice crosses involving N. sibuyanensis. I got this plant in trade so I didn't actually seek it out to add to the collection. My plant is still small so as more mature pitchers develop, I'll update them.
highlander (not a naturally occurring hybrid)
Cultivation: easy to moderate grower outdoors
Market availability: size 3 to possible larger plants; fairly available
Species variability: some among the seed grown plants
$ / size: moderate $30.00 and up
Cuttings: none available for trade