I've been unable to find a source either way. Can you help?

Just looking casually at topo maps and assuming the worst case I've seen (all land and sea ice melts, resulting in sea water rising 250'), the land we'll lose in coastal regions and major river basins is smaller than what we'll gain near the poles. Farming just Antarctica would probably produce enough food to feed the world several times over.

Edit: This isn't to say that worst case scenario wouldn't displace high percentages of the population or that that isn't a major issue; however, it's not an insurmountable obstacle given the gradual nature of the change.