Just a question for you guys: We have been emphasizing the one IP per node but we see only 1977 unique IPs for 2237 active MNs. So, how can we say that it is one IP per node? And, we can see that each MN is paid after roughly every 2237 blocks. So, someone is running multiple nodes on one IP.
EDIT: My guess is that these nodes are using NAT and the private IPs are in virtual instance of OS with private network stack. Then, the firewall distribute the incoming traffics to these virtual instance of OS. So, the one IP per node is not a real requirement. It just takes a little more effort to get around it. That brings back to my original suggestion: pay MN according to the number of darksend transactions served.