I might experiment with grafting at some point... I'm very curious about the couple papers I've read on graft-induced hybridization in peppers. It doesn't exactly sound practical as a hybridizing technique, but it seems there's some evidence to suggest that grafting a cotelydon-stage or otherwise early-growth scion onto one of the growing points of a much older plant can lead to one-way migration of genetic material into the scion growth beyond simple chimerism.
Sounds like something out of science-fiction to me, but there might be some merit to it.