In case of successful attack , it should be a option to check number of files (core joomla files) in strategic folders like:
includes, media, components. After I had this attack I have found some strange files (.php and .db) .
I mean a simple counting ex. media/system/js - has 16 core files etc.
Or tool similar to Version Verification Tool or Eyesite (from JED)
#2 idea:
Option to show history list of installed extensions with date like (only this):
com_akeebabackup - installed on 12 nov 2010 12:00 by Admin
com_jce - installed on 5 may 2009 12:22 by Zoozol
#3 idea:
System will check ID of super administrator so if it see that is still ID 62 - should ask you to change for security reasons.