My pedantic nature can't stand having unaligned columns in nodetool outputs, which happens when IP addresses are IPv6 ones:
I'm attaching a patch that fixes this problem for nodetool status / ring commands. It does it by picking first item in nodes list (for nodetool ring it's first node in general, for nodetool status it's first node in each DC) and uses its length as a field length for output.
It bases on assumptions that it's imppossible to have 0 nodes in cluster/DC and the lenghts of addresses are "similar". The alternative I'm considering too is finding the longest address - it will be 100% accurate.