Is there a complete cortico-cortical connectivity map based on a useful partitioning of the cortex? I have something like Brodmann Areas in mind, but any complete list of cortex regions would do. I'm primarily interested in human brains here. Ultimately I'd like enough information to be able to build an NxN matrix containing boolean "innervates" entries. Numbers representing an "innervation strength" would be great too.
Yes-- you may be very interested in the Human Connectome Project (also here), whose goal is to map human brain connectivity.

One of the primary tools used to map functional and anatomical connections is diffusion tensor imaging (DTI). Unlike the more often used T2-weighted images, DTI allows researchers to image white matter tracts directly.

The data from the HCP is available for free to researchers, but you need to apply for access. See their website for details.