I've put together a tutorial for grafting passiflora, check it out here:
Why graft passiflora? There are some species of passiflora from the cool mountains of South America that can't survive higher temperatures. These same plants grafted onto heat resistant root stocks (like Passiflora caerulea) will grow and flower where they otherwise wouldn't survive. The converse may also be true; grafting of heat loving plants onto cool loving rootstocks may perform better in cooler, wetter environments.
Let me know if you have any questions or comments.
Here is a link that might be useful: Grafting Passiflora Tutorial