Hmm, okay I think for discussion this is good, but we will not be able to arrive at solid numbers until comprehensive genetic research is actually done. Basically all that is being done is comparing the spelling of a couple snippets of DNA for differences. Have any alelles even been identified? No. (At least, not that I'm aware of) Genetic testing and understanding how DNA works are not really the same thing. While we can easily compare relationships between individuals and groups, by comparing random mutations, we can't actually read the DNA and directly understand what it translates into. Which genes on which of the 80 chromosomes are responsible for spelling out the differences that generate the peristome we see on Nepenthes tentaculata vs the peristome of N. hamata? And which alleles control the overall hairiness an individual displays? Clueless? Me too...
How many genes are basically the same in all species? No idea? Well, then it is currently impossible to say where to draw the line between complex hybrid vs. species based on the DNA an individual has acquired. Also, some groups of Nepenthes might tend to share more of their DNA than other groups.