My concerns are more along the lines of potential for DDoSing the network if you have infinite nodes (well 65000 per IP) and sybil attacks. But those are mostly because I haven't read enough of the networking code to realize all the possibilities (nor do I think anyone really has). If you spend enough time reading up on net.cpp and can convince people that those aren't a problem, then I'm sure it would get merged.
OK. That sounds pretty serious. These issues will have to be addressed for IPv6 as well, then.