The current checkuser extension does not show the hostname for each IP. While it is not too embarrassing (hostnames being easily retrievable), it would save a lot of time for checks on accounts using many different IPs.
Something like this would be more than fine:
(while viewing a user's IPs)
- 127.0.0.1 (localhost) (check) (block)
(while viewing the list of edits per IP or user)
- Link to a page that has been modified
- IP: 127.0.0.1 (localhost) UA: Mozilla/5.0 etc.