Can't see progress of rolling back SPID with KILL WITH STATUSONLY
Solution 1:
Nope it doesn't do anything. You cannot kill a spid that's rolling back. The rollback has to complete otherwise the database is transactionally inconsistent and becomes SUSPECT.
From BOL: KILL WITH STATUSONLY generates a report only if the session ID or UOW is currently being rolled back because of a previous KILL session ID|UOW statement.
In this case, it rolled back on its own so you won't be able to see progress.
Hope this helps.
Solution 2:
So it looks like you can kill a SPID that is currently in rollback. While I still don't have any insight into the internals of what's happening, it appears that once you execute a KILL you can then get the progress by using KILL WITH STATUSONLY.
As Paul indicates, this is pretty arbitrary...